drm/i915/cnl: Fix the CURSOR_COEFF_MASK used in DDI Vswing Programming
[linux-2.6-block.git] / drivers / gpu / drm / i915 / intel_ringbuffer.c
index 6c5f9958197d5541381e7c2838c909fe19fa1520..5224b7abb8a3d0a462a2b89ff46edbc1d646def7 100644 (file)
  */
 #define LEGACY_REQUEST_SIZE 200
 
-int __intel_ring_space(int head, int tail, int size)
+static unsigned int __intel_ring_space(unsigned int head,
+                                      unsigned int tail,
+                                      unsigned int size)
 {
-       int space = head - tail;
-       if (space <= 0)
-               space += size;
-       return space - I915_RING_FREE_SPACE;
+       /*
+        * "If the Ring Buffer Head Pointer and the Tail Pointer are on the
+        * same cacheline, the Head Pointer must not be greater than the Tail
+        * Pointer."
+        */
+       GEM_BUG_ON(!is_power_of_2(size));
+       return (head - tail - CACHELINE_BYTES) & (size - 1);
 }
 
-void intel_ring_update_space(struct intel_ring *ring)
+unsigned int intel_ring_update_space(struct intel_ring *ring)
 {
-       if (ring->last_retired_head != -1) {
-               ring->head = ring->last_retired_head;
-               ring->last_retired_head = -1;
-       }
+       unsigned int space;
 
-       ring->space = __intel_ring_space(ring->head & HEAD_ADDR,
-                                        ring->tail, ring->size);
+       space = __intel_ring_space(ring->head, ring->emit, ring->size);
+
+       ring->space = space;
+       return space;
 }
 
 static int
 gen2_render_ring_flush(struct drm_i915_gem_request *req, u32 mode)
 {
-       struct intel_ring *ring = req->ring;
-       u32 cmd;
-       int ret;
+       u32 cmd, *cs;
 
        cmd = MI_FLUSH;
 
        if (mode & EMIT_INVALIDATE)
                cmd |= MI_READ_FLUSH;
 
-       ret = intel_ring_begin(req, 2);
-       if (ret)
-               return ret;
+       cs = intel_ring_begin(req, 2);
+       if (IS_ERR(cs))
+               return PTR_ERR(cs);
 
-       intel_ring_emit(ring, cmd);
-       intel_ring_emit(ring, MI_NOOP);
-       intel_ring_advance(ring);
+       *cs++ = cmd;
+       *cs++ = MI_NOOP;
+       intel_ring_advance(req, cs);
 
        return 0;
 }
@@ -84,9 +86,7 @@ gen2_render_ring_flush(struct drm_i915_gem_request *req, u32 mode)
 static int
 gen4_render_ring_flush(struct drm_i915_gem_request *req, u32 mode)
 {
-       struct intel_ring *ring = req->ring;
-       u32 cmd;
-       int ret;
+       u32 cmd, *cs;
 
        /*
         * read/write caches:
@@ -123,13 +123,13 @@ gen4_render_ring_flush(struct drm_i915_gem_request *req, u32 mode)
                        cmd |= MI_INVALIDATE_ISP;
        }
 
-       ret = intel_ring_begin(req, 2);
-       if (ret)
-               return ret;
+       cs = intel_ring_begin(req, 2);
+       if (IS_ERR(cs))
+               return PTR_ERR(cs);
 
-       intel_ring_emit(ring, cmd);
-       intel_ring_emit(ring, MI_NOOP);
-       intel_ring_advance(ring);
+       *cs++ = cmd;
+       *cs++ = MI_NOOP;
+       intel_ring_advance(req, cs);
 
        return 0;
 }
@@ -174,35 +174,33 @@ gen4_render_ring_flush(struct drm_i915_gem_request *req, u32 mode)
 static int
 intel_emit_post_sync_nonzero_flush(struct drm_i915_gem_request *req)
 {
-       struct intel_ring *ring = req->ring;
        u32 scratch_addr =
                i915_ggtt_offset(req->engine->scratch) + 2 * CACHELINE_BYTES;
-       int ret;
-
-       ret = intel_ring_begin(req, 6);
-       if (ret)
-               return ret;
-
-       intel_ring_emit(ring, GFX_OP_PIPE_CONTROL(5));
-       intel_ring_emit(ring, PIPE_CONTROL_CS_STALL |
-                       PIPE_CONTROL_STALL_AT_SCOREBOARD);
-       intel_ring_emit(ring, scratch_addr | PIPE_CONTROL_GLOBAL_GTT);
-       intel_ring_emit(ring, 0); /* low dword */
-       intel_ring_emit(ring, 0); /* high dword */
-       intel_ring_emit(ring, MI_NOOP);
-       intel_ring_advance(ring);
-
-       ret = intel_ring_begin(req, 6);
-       if (ret)
-               return ret;
-
-       intel_ring_emit(ring, GFX_OP_PIPE_CONTROL(5));
-       intel_ring_emit(ring, PIPE_CONTROL_QW_WRITE);
-       intel_ring_emit(ring, scratch_addr | PIPE_CONTROL_GLOBAL_GTT);
-       intel_ring_emit(ring, 0);
-       intel_ring_emit(ring, 0);
-       intel_ring_emit(ring, MI_NOOP);
-       intel_ring_advance(ring);
+       u32 *cs;
+
+       cs = intel_ring_begin(req, 6);
+       if (IS_ERR(cs))
+               return PTR_ERR(cs);
+
+       *cs++ = GFX_OP_PIPE_CONTROL(5);
+       *cs++ = PIPE_CONTROL_CS_STALL | PIPE_CONTROL_STALL_AT_SCOREBOARD;
+       *cs++ = scratch_addr | PIPE_CONTROL_GLOBAL_GTT;
+       *cs++ = 0; /* low dword */
+       *cs++ = 0; /* high dword */
+       *cs++ = MI_NOOP;
+       intel_ring_advance(req, cs);
+
+       cs = intel_ring_begin(req, 6);
+       if (IS_ERR(cs))
+               return PTR_ERR(cs);
+
+       *cs++ = GFX_OP_PIPE_CONTROL(5);
+       *cs++ = PIPE_CONTROL_QW_WRITE;
+       *cs++ = scratch_addr | PIPE_CONTROL_GLOBAL_GTT;
+       *cs++ = 0;
+       *cs++ = 0;
+       *cs++ = MI_NOOP;
+       intel_ring_advance(req, cs);
 
        return 0;
 }
@@ -210,10 +208,9 @@ intel_emit_post_sync_nonzero_flush(struct drm_i915_gem_request *req)
 static int
 gen6_render_ring_flush(struct drm_i915_gem_request *req, u32 mode)
 {
-       struct intel_ring *ring = req->ring;
        u32 scratch_addr =
                i915_ggtt_offset(req->engine->scratch) + 2 * CACHELINE_BYTES;
-       u32 flags = 0;
+       u32 *cs, flags = 0;
        int ret;
 
        /* Force SNB workarounds for PIPE_CONTROL flushes */
@@ -247,15 +244,15 @@ gen6_render_ring_flush(struct drm_i915_gem_request *req, u32 mode)
                flags |= PIPE_CONTROL_QW_WRITE | PIPE_CONTROL_CS_STALL;
        }
 
-       ret = intel_ring_begin(req, 4);
-       if (ret)
-               return ret;
+       cs = intel_ring_begin(req, 4);
+       if (IS_ERR(cs))
+               return PTR_ERR(cs);
 
-       intel_ring_emit(ring, GFX_OP_PIPE_CONTROL(4));
-       intel_ring_emit(ring, flags);
-       intel_ring_emit(ring, scratch_addr | PIPE_CONTROL_GLOBAL_GTT);
-       intel_ring_emit(ring, 0);
-       intel_ring_advance(ring);
+       *cs++ = GFX_OP_PIPE_CONTROL(4);
+       *cs++ = flags;
+       *cs++ = scratch_addr | PIPE_CONTROL_GLOBAL_GTT;
+       *cs++ = 0;
+       intel_ring_advance(req, cs);
 
        return 0;
 }
@@ -263,20 +260,17 @@ gen6_render_ring_flush(struct drm_i915_gem_request *req, u32 mode)
 static int
 gen7_render_ring_cs_stall_wa(struct drm_i915_gem_request *req)
 {
-       struct intel_ring *ring = req->ring;
-       int ret;
+       u32 *cs;
 
-       ret = intel_ring_begin(req, 4);
-       if (ret)
-               return ret;
+       cs = intel_ring_begin(req, 4);
+       if (IS_ERR(cs))
+               return PTR_ERR(cs);
 
-       intel_ring_emit(ring, GFX_OP_PIPE_CONTROL(4));
-       intel_ring_emit(ring,
-                       PIPE_CONTROL_CS_STALL |
-                       PIPE_CONTROL_STALL_AT_SCOREBOARD);
-       intel_ring_emit(ring, 0);
-       intel_ring_emit(ring, 0);
-       intel_ring_advance(ring);
+       *cs++ = GFX_OP_PIPE_CONTROL(4);
+       *cs++ = PIPE_CONTROL_CS_STALL | PIPE_CONTROL_STALL_AT_SCOREBOARD;
+       *cs++ = 0;
+       *cs++ = 0;
+       intel_ring_advance(req, cs);
 
        return 0;
 }
@@ -284,11 +278,9 @@ gen7_render_ring_cs_stall_wa(struct drm_i915_gem_request *req)
 static int
 gen7_render_ring_flush(struct drm_i915_gem_request *req, u32 mode)
 {
-       struct intel_ring *ring = req->ring;
        u32 scratch_addr =
                i915_ggtt_offset(req->engine->scratch) + 2 * CACHELINE_BYTES;
-       u32 flags = 0;
-       int ret;
+       u32 *cs, flags = 0;
 
        /*
         * Ensure that any following seqno writes only happen when the render
@@ -332,37 +324,15 @@ gen7_render_ring_flush(struct drm_i915_gem_request *req, u32 mode)
                gen7_render_ring_cs_stall_wa(req);
        }
 
-       ret = intel_ring_begin(req, 4);
-       if (ret)
-               return ret;
-
-       intel_ring_emit(ring, GFX_OP_PIPE_CONTROL(4));
-       intel_ring_emit(ring, flags);
-       intel_ring_emit(ring, scratch_addr);
-       intel_ring_emit(ring, 0);
-       intel_ring_advance(ring);
-
-       return 0;
-}
-
-static int
-gen8_emit_pipe_control(struct drm_i915_gem_request *req,
-                      u32 flags, u32 scratch_addr)
-{
-       struct intel_ring *ring = req->ring;
-       int ret;
-
-       ret = intel_ring_begin(req, 6);
-       if (ret)
-               return ret;
+       cs = intel_ring_begin(req, 4);
+       if (IS_ERR(cs))
+               return PTR_ERR(cs);
 
-       intel_ring_emit(ring, GFX_OP_PIPE_CONTROL(6));
-       intel_ring_emit(ring, flags);
-       intel_ring_emit(ring, scratch_addr);
-       intel_ring_emit(ring, 0);
-       intel_ring_emit(ring, 0);
-       intel_ring_emit(ring, 0);
-       intel_ring_advance(ring);
+       *cs++ = GFX_OP_PIPE_CONTROL(4);
+       *cs++ = flags;
+       *cs++ = scratch_addr;
+       *cs++ = 0;
+       intel_ring_advance(req, cs);
 
        return 0;
 }
@@ -370,12 +340,14 @@ gen8_emit_pipe_control(struct drm_i915_gem_request *req,
 static int
 gen8_render_ring_flush(struct drm_i915_gem_request *req, u32 mode)
 {
-       u32 scratch_addr =
-               i915_ggtt_offset(req->engine->scratch) + 2 * CACHELINE_BYTES;
-       u32 flags = 0;
-       int ret;
+       u32 flags;
+       u32 *cs;
 
-       flags |= PIPE_CONTROL_CS_STALL;
+       cs = intel_ring_begin(req, mode & EMIT_INVALIDATE ? 12 : 6);
+       if (IS_ERR(cs))
+               return PTR_ERR(cs);
+
+       flags = PIPE_CONTROL_CS_STALL;
 
        if (mode & EMIT_FLUSH) {
                flags |= PIPE_CONTROL_RENDER_TARGET_CACHE_FLUSH;
@@ -394,15 +366,19 @@ gen8_render_ring_flush(struct drm_i915_gem_request *req, u32 mode)
                flags |= PIPE_CONTROL_GLOBAL_GTT_IVB;
 
                /* WaCsStallBeforeStateCacheInvalidate:bdw,chv */
-               ret = gen8_emit_pipe_control(req,
-                                            PIPE_CONTROL_CS_STALL |
-                                            PIPE_CONTROL_STALL_AT_SCOREBOARD,
-                                            0);
-               if (ret)
-                       return ret;
+               cs = gen8_emit_pipe_control(cs,
+                                           PIPE_CONTROL_CS_STALL |
+                                           PIPE_CONTROL_STALL_AT_SCOREBOARD,
+                                           0);
        }
 
-       return gen8_emit_pipe_control(req, flags, scratch_addr);
+       cs = gen8_emit_pipe_control(cs, flags,
+                                   i915_ggtt_offset(req->engine->scratch) +
+                                   2 * CACHELINE_BYTES);
+
+       intel_ring_advance(req, cs);
+
+       return 0;
 }
 
 static void ring_setup_phys_status_page(struct intel_engine_cs *engine)
@@ -572,9 +548,9 @@ static int init_ring_common(struct intel_engine_cs *engine)
        I915_WRITE_CTL(engine, RING_CTL_SIZE(ring->size) | RING_VALID);
 
        /* If the head is still not zero, the ring is dead */
-       if (intel_wait_for_register_fw(dev_priv, RING_CTL(engine->mmio_base),
-                                      RING_VALID, RING_VALID,
-                                      50)) {
+       if (intel_wait_for_register(dev_priv, RING_CTL(engine->mmio_base),
+                                   RING_VALID, RING_VALID,
+                                   50)) {
                DRM_ERROR("%s initialization failed "
                          "ctl %08x (valid? %d) head %08x [%08x] tail %08x [%08x] start %08x [expected %08x]\n",
                          engine->name,
@@ -646,52 +622,13 @@ static void reset_ring_common(struct intel_engine_cs *engine,
                }
 
                /* If the rq hung, jump to its breadcrumb and skip the batch */
-               if (request->fence.error == -EIO) {
-                       struct intel_ring *ring = request->ring;
-
-                       ring->head = request->postfix;
-                       ring->last_retired_head = -1;
-               }
+               if (request->fence.error == -EIO)
+                       request->ring->head = request->postfix;
        } else {
                engine->legacy_active_context = NULL;
        }
 }
 
-static int intel_ring_workarounds_emit(struct drm_i915_gem_request *req)
-{
-       struct intel_ring *ring = req->ring;
-       struct i915_workarounds *w = &req->i915->workarounds;
-       int ret, i;
-
-       if (w->count == 0)
-               return 0;
-
-       ret = req->engine->emit_flush(req, EMIT_BARRIER);
-       if (ret)
-               return ret;
-
-       ret = intel_ring_begin(req, (w->count * 2 + 2));
-       if (ret)
-               return ret;
-
-       intel_ring_emit(ring, MI_LOAD_REGISTER_IMM(w->count));
-       for (i = 0; i < w->count; i++) {
-               intel_ring_emit_reg(ring, w->reg[i].addr);
-               intel_ring_emit(ring, w->reg[i].value);
-       }
-       intel_ring_emit(ring, MI_NOOP);
-
-       intel_ring_advance(ring);
-
-       ret = req->engine->emit_flush(req, EMIT_BARRIER);
-       if (ret)
-               return ret;
-
-       DRM_DEBUG_DRIVER("Number of Workarounds emitted: %d\n", w->count);
-
-       return 0;
-}
-
 static int intel_rcs_ctx_init(struct drm_i915_gem_request *req)
 {
        int ret;
@@ -707,498 +644,6 @@ static int intel_rcs_ctx_init(struct drm_i915_gem_request *req)
        return 0;
 }
 
-static int wa_add(struct drm_i915_private *dev_priv,
-                 i915_reg_t addr,
-                 const u32 mask, const u32 val)
-{
-       const u32 idx = dev_priv->workarounds.count;
-
-       if (WARN_ON(idx >= I915_MAX_WA_REGS))
-               return -ENOSPC;
-
-       dev_priv->workarounds.reg[idx].addr = addr;
-       dev_priv->workarounds.reg[idx].value = val;
-       dev_priv->workarounds.reg[idx].mask = mask;
-
-       dev_priv->workarounds.count++;
-
-       return 0;
-}
-
-#define WA_REG(addr, mask, val) do { \
-               const int r = wa_add(dev_priv, (addr), (mask), (val)); \
-               if (r) \
-                       return r; \
-       } while (0)
-
-#define WA_SET_BIT_MASKED(addr, mask) \
-       WA_REG(addr, (mask), _MASKED_BIT_ENABLE(mask))
-
-#define WA_CLR_BIT_MASKED(addr, mask) \
-       WA_REG(addr, (mask), _MASKED_BIT_DISABLE(mask))
-
-#define WA_SET_FIELD_MASKED(addr, mask, value) \
-       WA_REG(addr, mask, _MASKED_FIELD(mask, value))
-
-#define WA_SET_BIT(addr, mask) WA_REG(addr, mask, I915_READ(addr) | (mask))
-#define WA_CLR_BIT(addr, mask) WA_REG(addr, mask, I915_READ(addr) & ~(mask))
-
-#define WA_WRITE(addr, val) WA_REG(addr, 0xffffffff, val)
-
-static int wa_ring_whitelist_reg(struct intel_engine_cs *engine,
-                                i915_reg_t reg)
-{
-       struct drm_i915_private *dev_priv = engine->i915;
-       struct i915_workarounds *wa = &dev_priv->workarounds;
-       const uint32_t index = wa->hw_whitelist_count[engine->id];
-
-       if (WARN_ON(index >= RING_MAX_NONPRIV_SLOTS))
-               return -EINVAL;
-
-       WA_WRITE(RING_FORCE_TO_NONPRIV(engine->mmio_base, index),
-                i915_mmio_reg_offset(reg));
-       wa->hw_whitelist_count[engine->id]++;
-
-       return 0;
-}
-
-static int gen8_init_workarounds(struct intel_engine_cs *engine)
-{
-       struct drm_i915_private *dev_priv = engine->i915;
-
-       WA_SET_BIT_MASKED(INSTPM, INSTPM_FORCE_ORDERING);
-
-       /* WaDisableAsyncFlipPerfMode:bdw,chv */
-       WA_SET_BIT_MASKED(MI_MODE, ASYNC_FLIP_PERF_DISABLE);
-
-       /* WaDisablePartialInstShootdown:bdw,chv */
-       WA_SET_BIT_MASKED(GEN8_ROW_CHICKEN,
-                         PARTIAL_INSTRUCTION_SHOOTDOWN_DISABLE);
-
-       /* Use Force Non-Coherent whenever executing a 3D context. This is a
-        * workaround for for a possible hang in the unlikely event a TLB
-        * invalidation occurs during a PSD flush.
-        */
-       /* WaForceEnableNonCoherent:bdw,chv */
-       /* WaHdcDisableFetchWhenMasked:bdw,chv */
-       WA_SET_BIT_MASKED(HDC_CHICKEN0,
-                         HDC_DONOT_FETCH_MEM_WHEN_MASKED |
-                         HDC_FORCE_NON_COHERENT);
-
-       /* From the Haswell PRM, Command Reference: Registers, CACHE_MODE_0:
-        * "The Hierarchical Z RAW Stall Optimization allows non-overlapping
-        *  polygons in the same 8x4 pixel/sample area to be processed without
-        *  stalling waiting for the earlier ones to write to Hierarchical Z
-        *  buffer."
-        *
-        * This optimization is off by default for BDW and CHV; turn it on.
-        */
-       WA_CLR_BIT_MASKED(CACHE_MODE_0_GEN7, HIZ_RAW_STALL_OPT_DISABLE);
-
-       /* Wa4x4STCOptimizationDisable:bdw,chv */
-       WA_SET_BIT_MASKED(CACHE_MODE_1, GEN8_4x4_STC_OPTIMIZATION_DISABLE);
-
-       /*
-        * BSpec recommends 8x4 when MSAA is used,
-        * however in practice 16x4 seems fastest.
-        *
-        * Note that PS/WM thread counts depend on the WIZ hashing
-        * disable bit, which we don't touch here, but it's good
-        * to keep in mind (see 3DSTATE_PS and 3DSTATE_WM).
-        */
-       WA_SET_FIELD_MASKED(GEN7_GT_MODE,
-                           GEN6_WIZ_HASHING_MASK,
-                           GEN6_WIZ_HASHING_16x4);
-
-       return 0;
-}
-
-static int bdw_init_workarounds(struct intel_engine_cs *engine)
-{
-       struct drm_i915_private *dev_priv = engine->i915;
-       int ret;
-
-       ret = gen8_init_workarounds(engine);
-       if (ret)
-               return ret;
-
-       /* WaDisableThreadStallDopClockGating:bdw (pre-production) */
-       WA_SET_BIT_MASKED(GEN8_ROW_CHICKEN, STALL_DOP_GATING_DISABLE);
-
-       /* WaDisableDopClockGating:bdw */
-       WA_SET_BIT_MASKED(GEN7_ROW_CHICKEN2,
-                         DOP_CLOCK_GATING_DISABLE);
-
-       WA_SET_BIT_MASKED(HALF_SLICE_CHICKEN3,
-                         GEN8_SAMPLER_POWER_BYPASS_DIS);
-
-       WA_SET_BIT_MASKED(HDC_CHICKEN0,
-                         /* WaForceContextSaveRestoreNonCoherent:bdw */
-                         HDC_FORCE_CONTEXT_SAVE_RESTORE_NON_COHERENT |
-                         /* WaDisableFenceDestinationToSLM:bdw (pre-prod) */
-                         (IS_BDW_GT3(dev_priv) ? HDC_FENCE_DEST_SLM_DISABLE : 0));
-
-       return 0;
-}
-
-static int chv_init_workarounds(struct intel_engine_cs *engine)
-{
-       struct drm_i915_private *dev_priv = engine->i915;
-       int ret;
-
-       ret = gen8_init_workarounds(engine);
-       if (ret)
-               return ret;
-
-       /* WaDisableThreadStallDopClockGating:chv */
-       WA_SET_BIT_MASKED(GEN8_ROW_CHICKEN, STALL_DOP_GATING_DISABLE);
-
-       /* Improve HiZ throughput on CHV. */
-       WA_SET_BIT_MASKED(HIZ_CHICKEN, CHV_HZ_8X8_MODE_IN_1X);
-
-       return 0;
-}
-
-static int gen9_init_workarounds(struct intel_engine_cs *engine)
-{
-       struct drm_i915_private *dev_priv = engine->i915;
-       int ret;
-
-       /* WaConextSwitchWithConcurrentTLBInvalidate:skl,bxt,kbl */
-       I915_WRITE(GEN9_CSFE_CHICKEN1_RCS, _MASKED_BIT_ENABLE(GEN9_PREEMPT_GPGPU_SYNC_SWITCH_DISABLE));
-
-       /* WaEnableLbsSlaRetryTimerDecrement:skl,bxt,kbl */
-       I915_WRITE(BDW_SCRATCH1, I915_READ(BDW_SCRATCH1) |
-                  GEN9_LBS_SLA_RETRY_TIMER_DECREMENT_ENABLE);
-
-       /* WaDisableKillLogic:bxt,skl,kbl */
-       I915_WRITE(GAM_ECOCHK, I915_READ(GAM_ECOCHK) |
-                  ECOCHK_DIS_TLB);
-
-       /* WaClearFlowControlGpgpuContextSave:skl,bxt,kbl */
-       /* WaDisablePartialInstShootdown:skl,bxt,kbl */
-       WA_SET_BIT_MASKED(GEN8_ROW_CHICKEN,
-                         FLOW_CONTROL_ENABLE |
-                         PARTIAL_INSTRUCTION_SHOOTDOWN_DISABLE);
-
-       /* Syncing dependencies between camera and graphics:skl,bxt,kbl */
-       WA_SET_BIT_MASKED(HALF_SLICE_CHICKEN3,
-                         GEN9_DISABLE_OCL_OOB_SUPPRESS_LOGIC);
-
-       /* WaDisableDgMirrorFixInHalfSliceChicken5:bxt */
-       if (IS_BXT_REVID(dev_priv, 0, BXT_REVID_A1))
-               WA_CLR_BIT_MASKED(GEN9_HALF_SLICE_CHICKEN5,
-                                 GEN9_DG_MIRROR_FIX_ENABLE);
-
-       /* WaSetDisablePixMaskCammingAndRhwoInCommonSliceChicken:bxt */
-       if (IS_BXT_REVID(dev_priv, 0, BXT_REVID_A1)) {
-               WA_SET_BIT_MASKED(GEN7_COMMON_SLICE_CHICKEN1,
-                                 GEN9_RHWO_OPTIMIZATION_DISABLE);
-               /*
-                * WA also requires GEN9_SLICE_COMMON_ECO_CHICKEN0[14:14] to be set
-                * but we do that in per ctx batchbuffer as there is an issue
-                * with this register not getting restored on ctx restore
-                */
-       }
-
-       /* WaEnableSamplerGPGPUPreemptionSupport:skl,bxt,kbl */
-       WA_SET_BIT_MASKED(GEN9_HALF_SLICE_CHICKEN7,
-                         GEN9_ENABLE_GPGPU_PREEMPTION);
-
-       /* Wa4x4STCOptimizationDisable:skl,bxt,kbl */
-       /* WaDisablePartialResolveInVc:skl,bxt,kbl */
-       WA_SET_BIT_MASKED(CACHE_MODE_1, (GEN8_4x4_STC_OPTIMIZATION_DISABLE |
-                                        GEN9_PARTIAL_RESOLVE_IN_VC_DISABLE));
-
-       /* WaCcsTlbPrefetchDisable:skl,bxt,kbl */
-       WA_CLR_BIT_MASKED(GEN9_HALF_SLICE_CHICKEN5,
-                         GEN9_CCS_TLB_PREFETCH_ENABLE);
-
-       /* WaDisableMaskBasedCammingInRCC:bxt */
-       if (IS_BXT_REVID(dev_priv, 0, BXT_REVID_A1))
-               WA_SET_BIT_MASKED(SLICE_ECO_CHICKEN0,
-                                 PIXEL_MASK_CAMMING_DISABLE);
-
-       /* WaForceContextSaveRestoreNonCoherent:skl,bxt,kbl */
-       WA_SET_BIT_MASKED(HDC_CHICKEN0,
-                         HDC_FORCE_CONTEXT_SAVE_RESTORE_NON_COHERENT |
-                         HDC_FORCE_CSR_NON_COHERENT_OVR_DISABLE);
-
-       /* WaForceEnableNonCoherent and WaDisableHDCInvalidation are
-        * both tied to WaForceContextSaveRestoreNonCoherent
-        * in some hsds for skl. We keep the tie for all gen9. The
-        * documentation is a bit hazy and so we want to get common behaviour,
-        * even though there is no clear evidence we would need both on kbl/bxt.
-        * This area has been source of system hangs so we play it safe
-        * and mimic the skl regardless of what bspec says.
-        *
-        * Use Force Non-Coherent whenever executing a 3D context. This
-        * is a workaround for a possible hang in the unlikely event
-        * a TLB invalidation occurs during a PSD flush.
-        */
-
-       /* WaForceEnableNonCoherent:skl,bxt,kbl */
-       WA_SET_BIT_MASKED(HDC_CHICKEN0,
-                         HDC_FORCE_NON_COHERENT);
-
-       /* WaDisableHDCInvalidation:skl,bxt,kbl */
-       I915_WRITE(GAM_ECOCHK, I915_READ(GAM_ECOCHK) |
-                  BDW_DISABLE_HDC_INVALIDATION);
-
-       /* WaDisableSamplerPowerBypassForSOPingPong:skl,bxt,kbl */
-       if (IS_SKYLAKE(dev_priv) ||
-           IS_KABYLAKE(dev_priv) ||
-           IS_BXT_REVID(dev_priv, 0, BXT_REVID_B0))
-               WA_SET_BIT_MASKED(HALF_SLICE_CHICKEN3,
-                                 GEN8_SAMPLER_POWER_BYPASS_DIS);
-
-       /* WaDisableSTUnitPowerOptimization:skl,bxt,kbl */
-       WA_SET_BIT_MASKED(HALF_SLICE_CHICKEN2, GEN8_ST_PO_DISABLE);
-
-       /* WaOCLCoherentLineFlush:skl,bxt,kbl */
-       I915_WRITE(GEN8_L3SQCREG4, (I915_READ(GEN8_L3SQCREG4) |
-                                   GEN8_LQSC_FLUSH_COHERENT_LINES));
-
-       /* WaVFEStateAfterPipeControlwithMediaStateClear:skl,bxt */
-       ret = wa_ring_whitelist_reg(engine, GEN9_CTX_PREEMPT_REG);
-       if (ret)
-               return ret;
-
-       /* WaEnablePreemptionGranularityControlByUMD:skl,bxt,kbl */
-       ret= wa_ring_whitelist_reg(engine, GEN8_CS_CHICKEN1);
-       if (ret)
-               return ret;
-
-       /* WaAllowUMDToModifyHDCChicken1:skl,bxt,kbl */
-       ret = wa_ring_whitelist_reg(engine, GEN8_HDC_CHICKEN1);
-       if (ret)
-               return ret;
-
-       return 0;
-}
-
-static int skl_tune_iz_hashing(struct intel_engine_cs *engine)
-{
-       struct drm_i915_private *dev_priv = engine->i915;
-       u8 vals[3] = { 0, 0, 0 };
-       unsigned int i;
-
-       for (i = 0; i < 3; i++) {
-               u8 ss;
-
-               /*
-                * Only consider slices where one, and only one, subslice has 7
-                * EUs
-                */
-               if (!is_power_of_2(INTEL_INFO(dev_priv)->sseu.subslice_7eu[i]))
-                       continue;
-
-               /*
-                * subslice_7eu[i] != 0 (because of the check above) and
-                * ss_max == 4 (maximum number of subslices possible per slice)
-                *
-                * ->    0 <= ss <= 3;
-                */
-               ss = ffs(INTEL_INFO(dev_priv)->sseu.subslice_7eu[i]) - 1;
-               vals[i] = 3 - ss;
-       }
-
-       if (vals[0] == 0 && vals[1] == 0 && vals[2] == 0)
-               return 0;
-
-       /* Tune IZ hashing. See intel_device_info_runtime_init() */
-       WA_SET_FIELD_MASKED(GEN7_GT_MODE,
-                           GEN9_IZ_HASHING_MASK(2) |
-                           GEN9_IZ_HASHING_MASK(1) |
-                           GEN9_IZ_HASHING_MASK(0),
-                           GEN9_IZ_HASHING(2, vals[2]) |
-                           GEN9_IZ_HASHING(1, vals[1]) |
-                           GEN9_IZ_HASHING(0, vals[0]));
-
-       return 0;
-}
-
-static int skl_init_workarounds(struct intel_engine_cs *engine)
-{
-       struct drm_i915_private *dev_priv = engine->i915;
-       int ret;
-
-       ret = gen9_init_workarounds(engine);
-       if (ret)
-               return ret;
-
-       /*
-        * Actual WA is to disable percontext preemption granularity control
-        * until D0 which is the default case so this is equivalent to
-        * !WaDisablePerCtxtPreemptionGranularityControl:skl
-        */
-       I915_WRITE(GEN7_FF_SLICE_CS_CHICKEN1,
-                  _MASKED_BIT_ENABLE(GEN9_FFSC_PERCTX_PREEMPT_CTRL));
-
-       /* WaEnableGapsTsvCreditFix:skl */
-       I915_WRITE(GEN8_GARBCNTL, (I915_READ(GEN8_GARBCNTL) |
-                                  GEN9_GAPS_TSV_CREDIT_DISABLE));
-
-       /* WaDisableGafsUnitClkGating:skl */
-       WA_SET_BIT(GEN7_UCGCTL4, GEN8_EU_GAUNIT_CLOCK_GATE_DISABLE);
-
-       /* WaInPlaceDecompressionHang:skl */
-       if (IS_SKL_REVID(dev_priv, SKL_REVID_H0, REVID_FOREVER))
-               WA_SET_BIT(GEN9_GAMT_ECO_REG_RW_IA,
-                          GAMT_ECO_ENABLE_IN_PLACE_DECOMPRESS);
-
-       /* WaDisableLSQCROPERFforOCL:skl */
-       ret = wa_ring_whitelist_reg(engine, GEN8_L3SQCREG4);
-       if (ret)
-               return ret;
-
-       return skl_tune_iz_hashing(engine);
-}
-
-static int bxt_init_workarounds(struct intel_engine_cs *engine)
-{
-       struct drm_i915_private *dev_priv = engine->i915;
-       int ret;
-
-       ret = gen9_init_workarounds(engine);
-       if (ret)
-               return ret;
-
-       /* WaStoreMultiplePTEenable:bxt */
-       /* This is a requirement according to Hardware specification */
-       if (IS_BXT_REVID(dev_priv, 0, BXT_REVID_A1))
-               I915_WRITE(TILECTL, I915_READ(TILECTL) | TILECTL_TLBPF);
-
-       /* WaSetClckGatingDisableMedia:bxt */
-       if (IS_BXT_REVID(dev_priv, 0, BXT_REVID_A1)) {
-               I915_WRITE(GEN7_MISCCPCTL, (I915_READ(GEN7_MISCCPCTL) &
-                                           ~GEN8_DOP_CLOCK_GATE_MEDIA_ENABLE));
-       }
-
-       /* WaDisableThreadStallDopClockGating:bxt */
-       WA_SET_BIT_MASKED(GEN8_ROW_CHICKEN,
-                         STALL_DOP_GATING_DISABLE);
-
-       /* WaDisablePooledEuLoadBalancingFix:bxt */
-       if (IS_BXT_REVID(dev_priv, BXT_REVID_B0, REVID_FOREVER)) {
-               WA_SET_BIT_MASKED(FF_SLICE_CS_CHICKEN2,
-                                 GEN9_POOLED_EU_LOAD_BALANCING_FIX_DISABLE);
-       }
-
-       /* WaDisableSbeCacheDispatchPortSharing:bxt */
-       if (IS_BXT_REVID(dev_priv, 0, BXT_REVID_B0)) {
-               WA_SET_BIT_MASKED(
-                       GEN7_HALF_SLICE_CHICKEN1,
-                       GEN7_SBE_SS_CACHE_DISPATCH_PORT_SHARING_DISABLE);
-       }
-
-       /* WaDisableObjectLevelPreemptionForTrifanOrPolygon:bxt */
-       /* WaDisableObjectLevelPreemptionForInstancedDraw:bxt */
-       /* WaDisableObjectLevelPreemtionForInstanceId:bxt */
-       /* WaDisableLSQCROPERFforOCL:bxt */
-       if (IS_BXT_REVID(dev_priv, 0, BXT_REVID_A1)) {
-               ret = wa_ring_whitelist_reg(engine, GEN9_CS_DEBUG_MODE1);
-               if (ret)
-                       return ret;
-
-               ret = wa_ring_whitelist_reg(engine, GEN8_L3SQCREG4);
-               if (ret)
-                       return ret;
-       }
-
-       /* WaProgramL3SqcReg1DefaultForPerf:bxt */
-       if (IS_BXT_REVID(dev_priv, BXT_REVID_B0, REVID_FOREVER))
-               I915_WRITE(GEN8_L3SQCREG1, L3_GENERAL_PRIO_CREDITS(62) |
-                                          L3_HIGH_PRIO_CREDITS(2));
-
-       /* WaToEnableHwFixForPushConstHWBug:bxt */
-       if (IS_BXT_REVID(dev_priv, BXT_REVID_C0, REVID_FOREVER))
-               WA_SET_BIT_MASKED(COMMON_SLICE_CHICKEN2,
-                                 GEN8_SBE_DISABLE_REPLAY_BUF_OPTIMIZATION);
-
-       /* WaInPlaceDecompressionHang:bxt */
-       if (IS_BXT_REVID(dev_priv, BXT_REVID_C0, REVID_FOREVER))
-               WA_SET_BIT(GEN9_GAMT_ECO_REG_RW_IA,
-                          GAMT_ECO_ENABLE_IN_PLACE_DECOMPRESS);
-
-       return 0;
-}
-
-static int kbl_init_workarounds(struct intel_engine_cs *engine)
-{
-       struct drm_i915_private *dev_priv = engine->i915;
-       int ret;
-
-       ret = gen9_init_workarounds(engine);
-       if (ret)
-               return ret;
-
-       /* WaEnableGapsTsvCreditFix:kbl */
-       I915_WRITE(GEN8_GARBCNTL, (I915_READ(GEN8_GARBCNTL) |
-                                  GEN9_GAPS_TSV_CREDIT_DISABLE));
-
-       /* WaDisableDynamicCreditSharing:kbl */
-       if (IS_KBL_REVID(dev_priv, 0, KBL_REVID_B0))
-               WA_SET_BIT(GAMT_CHKN_BIT_REG,
-                          GAMT_CHKN_DISABLE_DYNAMIC_CREDIT_SHARING);
-
-       /* WaDisableFenceDestinationToSLM:kbl (pre-prod) */
-       if (IS_KBL_REVID(dev_priv, KBL_REVID_A0, KBL_REVID_A0))
-               WA_SET_BIT_MASKED(HDC_CHICKEN0,
-                                 HDC_FENCE_DEST_SLM_DISABLE);
-
-       /* WaToEnableHwFixForPushConstHWBug:kbl */
-       if (IS_KBL_REVID(dev_priv, KBL_REVID_C0, REVID_FOREVER))
-               WA_SET_BIT_MASKED(COMMON_SLICE_CHICKEN2,
-                                 GEN8_SBE_DISABLE_REPLAY_BUF_OPTIMIZATION);
-
-       /* WaDisableGafsUnitClkGating:kbl */
-       WA_SET_BIT(GEN7_UCGCTL4, GEN8_EU_GAUNIT_CLOCK_GATE_DISABLE);
-
-       /* WaDisableSbeCacheDispatchPortSharing:kbl */
-       WA_SET_BIT_MASKED(
-               GEN7_HALF_SLICE_CHICKEN1,
-               GEN7_SBE_SS_CACHE_DISPATCH_PORT_SHARING_DISABLE);
-
-       /* WaInPlaceDecompressionHang:kbl */
-       WA_SET_BIT(GEN9_GAMT_ECO_REG_RW_IA,
-                  GAMT_ECO_ENABLE_IN_PLACE_DECOMPRESS);
-
-       /* WaDisableLSQCROPERFforOCL:kbl */
-       ret = wa_ring_whitelist_reg(engine, GEN8_L3SQCREG4);
-       if (ret)
-               return ret;
-
-       return 0;
-}
-
-int init_workarounds_ring(struct intel_engine_cs *engine)
-{
-       struct drm_i915_private *dev_priv = engine->i915;
-
-       WARN_ON(engine->id != RCS);
-
-       dev_priv->workarounds.count = 0;
-       dev_priv->workarounds.hw_whitelist_count[RCS] = 0;
-
-       if (IS_BROADWELL(dev_priv))
-               return bdw_init_workarounds(engine);
-
-       if (IS_CHERRYVIEW(dev_priv))
-               return chv_init_workarounds(engine);
-
-       if (IS_SKYLAKE(dev_priv))
-               return skl_init_workarounds(engine);
-
-       if (IS_BROXTON(dev_priv))
-               return bxt_init_workarounds(engine);
-
-       if (IS_KABYLAKE(dev_priv))
-               return kbl_init_workarounds(engine);
-
-       return 0;
-}
-
 static int init_render_ring(struct intel_engine_cs *engine)
 {
        struct drm_i915_private *dev_priv = engine->i915;
@@ -1257,7 +702,7 @@ static void render_ring_cleanup(struct intel_engine_cs *engine)
        i915_vma_unpin_and_release(&dev_priv->semaphore);
 }
 
-static u32 *gen8_rcs_signal(struct drm_i915_gem_request *req, u32 *out)
+static u32 *gen8_rcs_signal(struct drm_i915_gem_request *req, u32 *cs)
 {
        struct drm_i915_private *dev_priv = req->i915;
        struct intel_engine_cs *waiter;
@@ -1268,23 +713,22 @@ static u32 *gen8_rcs_signal(struct drm_i915_gem_request *req, u32 *out)
                if (gtt_offset == MI_SEMAPHORE_SYNC_INVALID)
                        continue;
 
-               *out++ = GFX_OP_PIPE_CONTROL(6);
-               *out++ = (PIPE_CONTROL_GLOBAL_GTT_IVB |
-                         PIPE_CONTROL_QW_WRITE |
-                         PIPE_CONTROL_CS_STALL);
-               *out++ = lower_32_bits(gtt_offset);
-               *out++ = upper_32_bits(gtt_offset);
-               *out++ = req->global_seqno;
-               *out++ = 0;
-               *out++ = (MI_SEMAPHORE_SIGNAL |
-                         MI_SEMAPHORE_TARGET(waiter->hw_id));
-               *out++ = 0;
+               *cs++ = GFX_OP_PIPE_CONTROL(6);
+               *cs++ = PIPE_CONTROL_GLOBAL_GTT_IVB | PIPE_CONTROL_QW_WRITE |
+                       PIPE_CONTROL_CS_STALL;
+               *cs++ = lower_32_bits(gtt_offset);
+               *cs++ = upper_32_bits(gtt_offset);
+               *cs++ = req->global_seqno;
+               *cs++ = 0;
+               *cs++ = MI_SEMAPHORE_SIGNAL |
+                       MI_SEMAPHORE_TARGET(waiter->hw_id);
+               *cs++ = 0;
        }
 
-       return out;
+       return cs;
 }
 
-static u32 *gen8_xcs_signal(struct drm_i915_gem_request *req, u32 *out)
+static u32 *gen8_xcs_signal(struct drm_i915_gem_request *req, u32 *cs)
 {
        struct drm_i915_private *dev_priv = req->i915;
        struct intel_engine_cs *waiter;
@@ -1295,19 +739,19 @@ static u32 *gen8_xcs_signal(struct drm_i915_gem_request *req, u32 *out)
                if (gtt_offset == MI_SEMAPHORE_SYNC_INVALID)
                        continue;
 
-               *out++ = (MI_FLUSH_DW + 1) | MI_FLUSH_DW_OP_STOREDW;
-               *out++ = lower_32_bits(gtt_offset) | MI_FLUSH_DW_USE_GTT;
-               *out++ = upper_32_bits(gtt_offset);
-               *out++ = req->global_seqno;
-               *out++ = (MI_SEMAPHORE_SIGNAL |
-                         MI_SEMAPHORE_TARGET(waiter->hw_id));
-               *out++ = 0;
+               *cs++ = (MI_FLUSH_DW + 1) | MI_FLUSH_DW_OP_STOREDW;
+               *cs++ = lower_32_bits(gtt_offset) | MI_FLUSH_DW_USE_GTT;
+               *cs++ = upper_32_bits(gtt_offset);
+               *cs++ = req->global_seqno;
+               *cs++ = MI_SEMAPHORE_SIGNAL |
+                       MI_SEMAPHORE_TARGET(waiter->hw_id);
+               *cs++ = 0;
        }
 
-       return out;
+       return cs;
 }
 
-static u32 *gen6_signal(struct drm_i915_gem_request *req, u32 *out)
+static u32 *gen6_signal(struct drm_i915_gem_request *req, u32 *cs)
 {
        struct drm_i915_private *dev_priv = req->i915;
        struct intel_engine_cs *engine;
@@ -1322,16 +766,16 @@ static u32 *gen6_signal(struct drm_i915_gem_request *req, u32 *out)
 
                mbox_reg = req->engine->semaphore.mbox.signal[engine->hw_id];
                if (i915_mmio_reg_valid(mbox_reg)) {
-                       *out++ = MI_LOAD_REGISTER_IMM(1);
-                       *out++ = i915_mmio_reg_offset(mbox_reg);
-                       *out++ = req->global_seqno;
+                       *cs++ = MI_LOAD_REGISTER_IMM(1);
+                       *cs++ = i915_mmio_reg_offset(mbox_reg);
+                       *cs++ = req->global_seqno;
                        num_rings++;
                }
        }
        if (num_rings & 1)
-               *out++ = MI_NOOP;
+               *cs++ = MI_NOOP;
 
-       return out;
+       return cs;
 }
 
 static void i9xx_submit_request(struct drm_i915_gem_request *request)
@@ -1340,18 +784,19 @@ static void i9xx_submit_request(struct drm_i915_gem_request *request)
 
        i915_gem_request_submit(request);
 
-       I915_WRITE_TAIL(request->engine, request->tail);
+       I915_WRITE_TAIL(request->engine,
+                       intel_ring_set_tail(request->ring, request->tail));
 }
 
-static void i9xx_emit_breadcrumb(struct drm_i915_gem_request *req,
-                                u32 *out)
+static void i9xx_emit_breadcrumb(struct drm_i915_gem_request *req, u32 *cs)
 {
-       *out++ = MI_STORE_DWORD_INDEX;
-       *out++ = I915_GEM_HWS_INDEX << MI_STORE_DWORD_INDEX_SHIFT;
-       *out++ = req->global_seqno;
-       *out++ = MI_USER_INTERRUPT;
+       *cs++ = MI_STORE_DWORD_INDEX;
+       *cs++ = I915_GEM_HWS_INDEX << MI_STORE_DWORD_INDEX_SHIFT;
+       *cs++ = req->global_seqno;
+       *cs++ = MI_USER_INTERRUPT;
 
-       req->tail = intel_ring_offset(req->ring, out);
+       req->tail = intel_ring_offset(req, cs);
+       assert_ring_tail_valid(req->ring, req->tail);
 }
 
 static const int i9xx_emit_breadcrumb_sz = 4;
@@ -1364,34 +809,33 @@ static const int i9xx_emit_breadcrumb_sz = 4;
  * Update the mailbox registers in the *other* rings with the current seqno.
  * This acts like a signal in the canonical semaphore.
  */
-static void gen6_sema_emit_breadcrumb(struct drm_i915_gem_request *req,
-                                     u32 *out)
+static void gen6_sema_emit_breadcrumb(struct drm_i915_gem_request *req, u32 *cs)
 {
        return i9xx_emit_breadcrumb(req,
-                                   req->engine->semaphore.signal(req, out));
+                                   req->engine->semaphore.signal(req, cs));
 }
 
 static void gen8_render_emit_breadcrumb(struct drm_i915_gem_request *req,
-                                       u32 *out)
+                                       u32 *cs)
 {
        struct intel_engine_cs *engine = req->engine;
 
        if (engine->semaphore.signal)
-               out = engine->semaphore.signal(req, out);
-
-       *out++ = GFX_OP_PIPE_CONTROL(6);
-       *out++ = (PIPE_CONTROL_GLOBAL_GTT_IVB |
-                              PIPE_CONTROL_CS_STALL |
-                              PIPE_CONTROL_QW_WRITE);
-       *out++ = intel_hws_seqno_address(engine);
-       *out++ = 0;
-       *out++ = req->global_seqno;
+               cs = engine->semaphore.signal(req, cs);
+
+       *cs++ = GFX_OP_PIPE_CONTROL(6);
+       *cs++ = PIPE_CONTROL_GLOBAL_GTT_IVB | PIPE_CONTROL_CS_STALL |
+               PIPE_CONTROL_QW_WRITE;
+       *cs++ = intel_hws_seqno_address(engine);
+       *cs++ = 0;
+       *cs++ = req->global_seqno;
        /* We're thrashing one dword of HWS. */
-       *out++ = 0;
-       *out++ = MI_USER_INTERRUPT;
-       *out++ = MI_NOOP;
+       *cs++ = 0;
+       *cs++ = MI_USER_INTERRUPT;
+       *cs++ = MI_NOOP;
 
-       req->tail = intel_ring_offset(req->ring, out);
+       req->tail = intel_ring_offset(req, cs);
+       assert_ring_tail_valid(req->ring, req->tail);
 }
 
 static const int gen8_render_emit_breadcrumb_sz = 8;
@@ -1408,24 +852,21 @@ static int
 gen8_ring_sync_to(struct drm_i915_gem_request *req,
                  struct drm_i915_gem_request *signal)
 {
-       struct intel_ring *ring = req->ring;
        struct drm_i915_private *dev_priv = req->i915;
        u64 offset = GEN8_WAIT_OFFSET(req->engine, signal->engine->id);
        struct i915_hw_ppgtt *ppgtt;
-       int ret;
+       u32 *cs;
 
-       ret = intel_ring_begin(req, 4);
-       if (ret)
-               return ret;
+       cs = intel_ring_begin(req, 4);
+       if (IS_ERR(cs))
+               return PTR_ERR(cs);
 
-       intel_ring_emit(ring,
-                       MI_SEMAPHORE_WAIT |
-                       MI_SEMAPHORE_GLOBAL_GTT |
-                       MI_SEMAPHORE_SAD_GTE_SDD);
-       intel_ring_emit(ring, signal->global_seqno);
-       intel_ring_emit(ring, lower_32_bits(offset));
-       intel_ring_emit(ring, upper_32_bits(offset));
-       intel_ring_advance(ring);
+       *cs++ = MI_SEMAPHORE_WAIT | MI_SEMAPHORE_GLOBAL_GTT |
+               MI_SEMAPHORE_SAD_GTE_SDD;
+       *cs++ = signal->global_seqno;
+       *cs++ = lower_32_bits(offset);
+       *cs++ = upper_32_bits(offset);
+       intel_ring_advance(req, cs);
 
        /* When the !RCS engines idle waiting upon a semaphore, they lose their
         * pagetables and we must reload them before executing the batch.
@@ -1442,28 +883,27 @@ static int
 gen6_ring_sync_to(struct drm_i915_gem_request *req,
                  struct drm_i915_gem_request *signal)
 {
-       struct intel_ring *ring = req->ring;
        u32 dw1 = MI_SEMAPHORE_MBOX |
                  MI_SEMAPHORE_COMPARE |
                  MI_SEMAPHORE_REGISTER;
        u32 wait_mbox = signal->engine->semaphore.mbox.wait[req->engine->hw_id];
-       int ret;
+       u32 *cs;
 
        WARN_ON(wait_mbox == MI_SEMAPHORE_SYNC_INVALID);
 
-       ret = intel_ring_begin(req, 4);
-       if (ret)
-               return ret;
+       cs = intel_ring_begin(req, 4);
+       if (IS_ERR(cs))
+               return PTR_ERR(cs);
 
-       intel_ring_emit(ring, dw1 | wait_mbox);
+       *cs++ = dw1 | wait_mbox;
        /* Throughout all of the GEM code, seqno passed implies our current
         * seqno is >= the last seqno executed. However for hardware the
         * comparison is strictly greater than.
         */
-       intel_ring_emit(ring, signal->global_seqno - 1);
-       intel_ring_emit(ring, 0);
-       intel_ring_emit(ring, MI_NOOP);
-       intel_ring_advance(ring);
+       *cs++ = signal->global_seqno - 1;
+       *cs++ = 0;
+       *cs++ = MI_NOOP;
+       intel_ring_advance(req, cs);
 
        return 0;
 }
@@ -1564,16 +1004,15 @@ i8xx_irq_disable(struct intel_engine_cs *engine)
 static int
 bsd_ring_flush(struct drm_i915_gem_request *req, u32 mode)
 {
-       struct intel_ring *ring = req->ring;
-       int ret;
+       u32 *cs;
 
-       ret = intel_ring_begin(req, 2);
-       if (ret)
-               return ret;
+       cs = intel_ring_begin(req, 2);
+       if (IS_ERR(cs))
+               return PTR_ERR(cs);
 
-       intel_ring_emit(ring, MI_FLUSH);
-       intel_ring_emit(ring, MI_NOOP);
-       intel_ring_advance(ring);
+       *cs++ = MI_FLUSH;
+       *cs++ = MI_NOOP;
+       intel_ring_advance(req, cs);
        return 0;
 }
 
@@ -1639,20 +1078,16 @@ i965_emit_bb_start(struct drm_i915_gem_request *req,
                   u64 offset, u32 length,
                   unsigned int dispatch_flags)
 {
-       struct intel_ring *ring = req->ring;
-       int ret;
+       u32 *cs;
 
-       ret = intel_ring_begin(req, 2);
-       if (ret)
-               return ret;
+       cs = intel_ring_begin(req, 2);
+       if (IS_ERR(cs))
+               return PTR_ERR(cs);
 
-       intel_ring_emit(ring,
-                       MI_BATCH_BUFFER_START |
-                       MI_BATCH_GTT |
-                       (dispatch_flags & I915_DISPATCH_SECURE ?
-                        0 : MI_BATCH_NON_SECURE_I965));
-       intel_ring_emit(ring, offset);
-       intel_ring_advance(ring);
+       *cs++ = MI_BATCH_BUFFER_START | MI_BATCH_GTT | (dispatch_flags &
+               I915_DISPATCH_SECURE ? 0 : MI_BATCH_NON_SECURE_I965);
+       *cs++ = offset;
+       intel_ring_advance(req, cs);
 
        return 0;
 }
@@ -1666,59 +1101,56 @@ i830_emit_bb_start(struct drm_i915_gem_request *req,
                   u64 offset, u32 len,
                   unsigned int dispatch_flags)
 {
-       struct intel_ring *ring = req->ring;
-       u32 cs_offset = i915_ggtt_offset(req->engine->scratch);
-       int ret;
+       u32 *cs, cs_offset = i915_ggtt_offset(req->engine->scratch);
 
-       ret = intel_ring_begin(req, 6);
-       if (ret)
-               return ret;
+       cs = intel_ring_begin(req, 6);
+       if (IS_ERR(cs))
+               return PTR_ERR(cs);
 
        /* Evict the invalid PTE TLBs */
-       intel_ring_emit(ring, COLOR_BLT_CMD | BLT_WRITE_RGBA);
-       intel_ring_emit(ring, BLT_DEPTH_32 | BLT_ROP_COLOR_COPY | 4096);
-       intel_ring_emit(ring, I830_TLB_ENTRIES << 16 | 4); /* load each page */
-       intel_ring_emit(ring, cs_offset);
-       intel_ring_emit(ring, 0xdeadbeef);
-       intel_ring_emit(ring, MI_NOOP);
-       intel_ring_advance(ring);
+       *cs++ = COLOR_BLT_CMD | BLT_WRITE_RGBA;
+       *cs++ = BLT_DEPTH_32 | BLT_ROP_COLOR_COPY | 4096;
+       *cs++ = I830_TLB_ENTRIES << 16 | 4; /* load each page */
+       *cs++ = cs_offset;
+       *cs++ = 0xdeadbeef;
+       *cs++ = MI_NOOP;
+       intel_ring_advance(req, cs);
 
        if ((dispatch_flags & I915_DISPATCH_PINNED) == 0) {
                if (len > I830_BATCH_LIMIT)
                        return -ENOSPC;
 
-               ret = intel_ring_begin(req, 6 + 2);
-               if (ret)
-                       return ret;
+               cs = intel_ring_begin(req, 6 + 2);
+               if (IS_ERR(cs))
+                       return PTR_ERR(cs);
 
                /* Blit the batch (which has now all relocs applied) to the
                 * stable batch scratch bo area (so that the CS never
                 * stumbles over its tlb invalidation bug) ...
                 */
-               intel_ring_emit(ring, SRC_COPY_BLT_CMD | BLT_WRITE_RGBA);
-               intel_ring_emit(ring,
-                               BLT_DEPTH_32 | BLT_ROP_SRC_COPY | 4096);
-               intel_ring_emit(ring, DIV_ROUND_UP(len, 4096) << 16 | 4096);
-               intel_ring_emit(ring, cs_offset);
-               intel_ring_emit(ring, 4096);
-               intel_ring_emit(ring, offset);
-
-               intel_ring_emit(ring, MI_FLUSH);
-               intel_ring_emit(ring, MI_NOOP);
-               intel_ring_advance(ring);
+               *cs++ = SRC_COPY_BLT_CMD | BLT_WRITE_RGBA;
+               *cs++ = BLT_DEPTH_32 | BLT_ROP_SRC_COPY | 4096;
+               *cs++ = DIV_ROUND_UP(len, 4096) << 16 | 4096;
+               *cs++ = cs_offset;
+               *cs++ = 4096;
+               *cs++ = offset;
+
+               *cs++ = MI_FLUSH;
+               *cs++ = MI_NOOP;
+               intel_ring_advance(req, cs);
 
                /* ... and execute it. */
                offset = cs_offset;
        }
 
-       ret = intel_ring_begin(req, 2);
-       if (ret)
-               return ret;
+       cs = intel_ring_begin(req, 2);
+       if (IS_ERR(cs))
+               return PTR_ERR(cs);
 
-       intel_ring_emit(ring, MI_BATCH_BUFFER_START | MI_BATCH_GTT);
-       intel_ring_emit(ring, offset | (dispatch_flags & I915_DISPATCH_SECURE ?
-                                       0 : MI_BATCH_NON_SECURE));
-       intel_ring_advance(ring);
+       *cs++ = MI_BATCH_BUFFER_START | MI_BATCH_GTT;
+       *cs++ = offset | (dispatch_flags & I915_DISPATCH_SECURE ? 0 :
+               MI_BATCH_NON_SECURE);
+       intel_ring_advance(req, cs);
 
        return 0;
 }
@@ -1728,17 +1160,16 @@ i915_emit_bb_start(struct drm_i915_gem_request *req,
                   u64 offset, u32 len,
                   unsigned int dispatch_flags)
 {
-       struct intel_ring *ring = req->ring;
-       int ret;
+       u32 *cs;
 
-       ret = intel_ring_begin(req, 2);
-       if (ret)
-               return ret;
+       cs = intel_ring_begin(req, 2);
+       if (IS_ERR(cs))
+               return PTR_ERR(cs);
 
-       intel_ring_emit(ring, MI_BATCH_BUFFER_START | MI_BATCH_GTT);
-       intel_ring_emit(ring, offset | (dispatch_flags & I915_DISPATCH_SECURE ?
-                                       0 : MI_BATCH_NON_SECURE));
-       intel_ring_advance(ring);
+       *cs++ = MI_BATCH_BUFFER_START | MI_BATCH_GTT;
+       *cs++ = offset | (dispatch_flags & I915_DISPATCH_SECURE ? 0 :
+               MI_BATCH_NON_SECURE);
+       intel_ring_advance(req, cs);
 
        return 0;
 }
@@ -1838,6 +1269,8 @@ static int init_phys_status_page(struct intel_engine_cs *engine)
 {
        struct drm_i915_private *dev_priv = engine->i915;
 
+       GEM_BUG_ON(engine->id != RCS);
+
        dev_priv->status_page_dmah =
                drm_pci_alloc(&dev_priv->drm, PAGE_SIZE, PAGE_SIZE);
        if (!dev_priv->status_page_dmah)
@@ -1849,17 +1282,18 @@ static int init_phys_status_page(struct intel_engine_cs *engine)
        return 0;
 }
 
-int intel_ring_pin(struct intel_ring *ring, unsigned int offset_bias)
+int intel_ring_pin(struct intel_ring *ring,
+                  struct drm_i915_private *i915,
+                  unsigned int offset_bias)
 {
-       unsigned int flags;
-       enum i915_map_type map;
+       enum i915_map_type map = HAS_LLC(i915) ? I915_MAP_WB : I915_MAP_WC;
        struct i915_vma *vma = ring->vma;
+       unsigned int flags;
        void *addr;
        int ret;
 
        GEM_BUG_ON(ring->vaddr);
 
-       map = HAS_LLC(ring->engine->i915) ? I915_MAP_WB : I915_MAP_WC;
 
        flags = PIN_GLOBAL;
        if (offset_bias)
@@ -1895,11 +1329,23 @@ err:
        return PTR_ERR(addr);
 }
 
+void intel_ring_reset(struct intel_ring *ring, u32 tail)
+{
+       GEM_BUG_ON(!list_empty(&ring->request_list));
+       ring->tail = tail;
+       ring->head = tail;
+       ring->emit = tail;
+       intel_ring_update_space(ring);
+}
+
 void intel_ring_unpin(struct intel_ring *ring)
 {
        GEM_BUG_ON(!ring->vma);
        GEM_BUG_ON(!ring->vaddr);
 
+       /* Discard any unused bytes beyond that submitted to hw. */
+       intel_ring_reset(ring, ring->tail);
+
        if (i915_vma_is_map_and_fenceable(ring->vma))
                i915_vma_unpin_iomap(ring->vma);
        else
@@ -1917,7 +1363,7 @@ intel_ring_create_vma(struct drm_i915_private *dev_priv, int size)
 
        obj = i915_gem_object_create_stolen(dev_priv, size);
        if (!obj)
-               obj = i915_gem_object_create(dev_priv, size);
+               obj = i915_gem_object_create_internal(dev_priv, size);
        if (IS_ERR(obj))
                return ERR_CAST(obj);
 
@@ -1948,8 +1394,6 @@ intel_engine_create_ring(struct intel_engine_cs *engine, int size)
        if (!ring)
                return ERR_PTR(-ENOMEM);
 
-       ring->engine = engine;
-
        INIT_LIST_HEAD(&ring->request_list);
 
        ring->size = size;
@@ -1961,7 +1405,6 @@ intel_engine_create_ring(struct intel_engine_cs *engine, int size)
        if (IS_I830(engine->i915) || IS_I845G(engine->i915))
                ring->effective_size -= 2 * CACHELINE_BYTES;
 
-       ring->last_retired_head = -1;
        intel_ring_update_space(ring);
 
        vma = intel_ring_create_vma(engine->i915, size);
@@ -1985,7 +1428,7 @@ intel_ring_free(struct intel_ring *ring)
        kfree(ring);
 }
 
-static int context_pin(struct i915_gem_context *ctx, unsigned int flags)
+static int context_pin(struct i915_gem_context *ctx)
 {
        struct i915_vma *vma = ctx->engine[RCS].state;
        int ret;
@@ -2000,30 +1443,77 @@ static int context_pin(struct i915_gem_context *ctx, unsigned int flags)
                        return ret;
        }
 
-       return i915_vma_pin(vma, 0, ctx->ggtt_alignment, PIN_GLOBAL | flags);
+       return i915_vma_pin(vma, 0, I915_GTT_MIN_ALIGNMENT,
+                           PIN_GLOBAL | PIN_HIGH);
+}
+
+static struct i915_vma *
+alloc_context_vma(struct intel_engine_cs *engine)
+{
+       struct drm_i915_private *i915 = engine->i915;
+       struct drm_i915_gem_object *obj;
+       struct i915_vma *vma;
+
+       obj = i915_gem_object_create(i915, engine->context_size);
+       if (IS_ERR(obj))
+               return ERR_CAST(obj);
+
+       /*
+        * Try to make the context utilize L3 as well as LLC.
+        *
+        * On VLV we don't have L3 controls in the PTEs so we
+        * shouldn't touch the cache level, especially as that
+        * would make the object snooped which might have a
+        * negative performance impact.
+        *
+        * Snooping is required on non-llc platforms in execlist
+        * mode, but since all GGTT accesses use PAT entry 0 we
+        * get snooping anyway regardless of cache_level.
+        *
+        * This is only applicable for Ivy Bridge devices since
+        * later platforms don't have L3 control bits in the PTE.
+        */
+       if (IS_IVYBRIDGE(i915)) {
+               /* Ignore any error, regard it as a simple optimisation */
+               i915_gem_object_set_cache_level(obj, I915_CACHE_L3_LLC);
+       }
+
+       vma = i915_vma_instance(obj, &i915->ggtt.base, NULL);
+       if (IS_ERR(vma))
+               i915_gem_object_put(obj);
+
+       return vma;
 }
 
-static int intel_ring_context_pin(struct intel_engine_cs *engine,
-                                 struct i915_gem_context *ctx)
+static struct intel_ring *
+intel_ring_context_pin(struct intel_engine_cs *engine,
+                      struct i915_gem_context *ctx)
 {
        struct intel_context *ce = &ctx->engine[engine->id];
        int ret;
 
        lockdep_assert_held(&ctx->i915->drm.struct_mutex);
 
-       if (ce->pin_count++)
-               return 0;
+       if (likely(ce->pin_count++))
+               goto out;
+       GEM_BUG_ON(!ce->pin_count); /* no overflow please! */
 
-       if (ce->state) {
-               unsigned int flags;
+       if (!ce->state && engine->context_size) {
+               struct i915_vma *vma;
+
+               vma = alloc_context_vma(engine);
+               if (IS_ERR(vma)) {
+                       ret = PTR_ERR(vma);
+                       goto err;
+               }
 
-               flags = 0;
-               if (i915_gem_context_is_kernel(ctx))
-                       flags = PIN_HIGH;
+               ce->state = vma;
+       }
 
-               ret = context_pin(ctx, flags);
+       if (ce->state) {
+               ret = context_pin(ctx);
                if (ret)
-                       goto error;
+                       goto err;
 
                ce->state->obj->mm.dirty = true;
        }
@@ -2039,11 +1529,14 @@ static int intel_ring_context_pin(struct intel_engine_cs *engine,
                ce->initialised = true;
 
        i915_gem_context_get(ctx);
-       return 0;
 
-error:
+out:
+       /* One ringbuffer to rule them all */
+       return engine->buffer;
+
+err:
        ce->pin_count = 0;
-       return ret;
+       return ERR_PTR(ret);
 }
 
 static void intel_ring_context_unpin(struct intel_engine_cs *engine,
@@ -2065,78 +1558,70 @@ static void intel_ring_context_unpin(struct intel_engine_cs *engine,
 
 static int intel_init_ring_buffer(struct intel_engine_cs *engine)
 {
-       struct drm_i915_private *dev_priv = engine->i915;
        struct intel_ring *ring;
-       int ret;
-
-       WARN_ON(engine->buffer);
+       int err;
 
        intel_engine_setup_common(engine);
 
-       ret = intel_engine_init_common(engine);
-       if (ret)
-               goto error;
+       err = intel_engine_init_common(engine);
+       if (err)
+               goto err;
+
+       if (HWS_NEEDS_PHYSICAL(engine->i915))
+               err = init_phys_status_page(engine);
+       else
+               err = init_status_page(engine);
+       if (err)
+               goto err;
 
        ring = intel_engine_create_ring(engine, 32 * PAGE_SIZE);
        if (IS_ERR(ring)) {
-               ret = PTR_ERR(ring);
-               goto error;
-       }
-
-       if (HWS_NEEDS_PHYSICAL(dev_priv)) {
-               WARN_ON(engine->id != RCS);
-               ret = init_phys_status_page(engine);
-               if (ret)
-                       goto error;
-       } else {
-               ret = init_status_page(engine);
-               if (ret)
-                       goto error;
+               err = PTR_ERR(ring);
+               goto err_hws;
        }
 
        /* Ring wraparound at offset 0 sometimes hangs. No idea why. */
-       ret = intel_ring_pin(ring, I915_GTT_PAGE_SIZE);
-       if (ret) {
-               intel_ring_free(ring);
-               goto error;
-       }
+       err = intel_ring_pin(ring, engine->i915, I915_GTT_PAGE_SIZE);
+       if (err)
+               goto err_ring;
+
+       GEM_BUG_ON(engine->buffer);
        engine->buffer = ring;
 
        return 0;
 
-error:
-       intel_engine_cleanup(engine);
-       return ret;
+err_ring:
+       intel_ring_free(ring);
+err_hws:
+       if (HWS_NEEDS_PHYSICAL(engine->i915))
+               cleanup_phys_status_page(engine);
+       else
+               cleanup_status_page(engine);
+err:
+       intel_engine_cleanup_common(engine);
+       return err;
 }
 
 void intel_engine_cleanup(struct intel_engine_cs *engine)
 {
-       struct drm_i915_private *dev_priv;
-
-       dev_priv = engine->i915;
+       struct drm_i915_private *dev_priv = engine->i915;
 
-       if (engine->buffer) {
-               WARN_ON(INTEL_GEN(dev_priv) > 2 &&
-                       (I915_READ_MODE(engine) & MODE_IDLE) == 0);
+       WARN_ON(INTEL_GEN(dev_priv) > 2 &&
+               (I915_READ_MODE(engine) & MODE_IDLE) == 0);
 
-               intel_ring_unpin(engine->buffer);
-               intel_ring_free(engine->buffer);
-               engine->buffer = NULL;
-       }
+       intel_ring_unpin(engine->buffer);
+       intel_ring_free(engine->buffer);
 
        if (engine->cleanup)
                engine->cleanup(engine);
 
-       if (HWS_NEEDS_PHYSICAL(dev_priv)) {
-               WARN_ON(engine->id != RCS);
+       if (HWS_NEEDS_PHYSICAL(dev_priv))
                cleanup_phys_status_page(engine);
-       } else {
+       else
                cleanup_status_page(engine);
-       }
 
        intel_engine_cleanup_common(engine);
 
-       engine->i915 = NULL;
        dev_priv->engine[engine->id] = NULL;
        kfree(engine);
 }
@@ -2146,15 +1631,14 @@ void intel_legacy_submission_resume(struct drm_i915_private *dev_priv)
        struct intel_engine_cs *engine;
        enum intel_engine_id id;
 
-       for_each_engine(engine, dev_priv, id) {
-               engine->buffer->head = engine->buffer->tail;
-               engine->buffer->last_retired_head = -1;
-       }
+       /* Restart from the beginning of the rings for convenience */
+       for_each_engine(engine, dev_priv, id)
+               intel_ring_reset(engine->buffer, 0);
 }
 
 static int ring_request_alloc(struct drm_i915_gem_request *request)
 {
-       int ret;
+       u32 *cs;
 
        GEM_BUG_ON(!request->ctx->engine[request->engine->id].pin_count);
 
@@ -2164,18 +1648,16 @@ static int ring_request_alloc(struct drm_i915_gem_request *request)
         */
        request->reserved_space += LEGACY_REQUEST_SIZE;
 
-       GEM_BUG_ON(!request->engine->buffer);
-       request->ring = request->engine->buffer;
-
-       ret = intel_ring_begin(request, 0);
-       if (ret)
-               return ret;
+       cs = intel_ring_begin(request, 0);
+       if (IS_ERR(cs))
+               return PTR_ERR(cs);
 
        request->reserved_space -= LEGACY_REQUEST_SIZE;
        return 0;
 }
 
-static int wait_for_space(struct drm_i915_gem_request *req, int bytes)
+static noinline int wait_for_space(struct drm_i915_gem_request *req,
+                                  unsigned int bytes)
 {
        struct intel_ring *ring = req->ring;
        struct drm_i915_gem_request *target;
@@ -2183,8 +1665,7 @@ static int wait_for_space(struct drm_i915_gem_request *req, int bytes)
 
        lockdep_assert_held(&req->i915->drm.struct_mutex);
 
-       intel_ring_update_space(ring);
-       if (ring->space >= bytes)
+       if (intel_ring_update_space(ring) >= bytes)
                return 0;
 
        /*
@@ -2199,12 +1680,9 @@ static int wait_for_space(struct drm_i915_gem_request *req, int bytes)
        GEM_BUG_ON(!req->reserved_space);
 
        list_for_each_entry(target, &ring->request_list, ring_link) {
-               unsigned space;
-
                /* Would completion of this request free enough space? */
-               space = __intel_ring_space(target->postfix, ring->tail,
-                                          ring->size);
-               if (space >= bytes)
+               if (bytes <= __intel_ring_space(target->postfix,
+                                               ring->emit, ring->size))
                        break;
        }
 
@@ -2224,78 +1702,87 @@ static int wait_for_space(struct drm_i915_gem_request *req, int bytes)
        return 0;
 }
 
-int intel_ring_begin(struct drm_i915_gem_request *req, int num_dwords)
+u32 *intel_ring_begin(struct drm_i915_gem_request *req,
+                     unsigned int num_dwords)
 {
        struct intel_ring *ring = req->ring;
-       int remain_actual = ring->size - ring->tail;
-       int remain_usable = ring->effective_size - ring->tail;
-       int bytes = num_dwords * sizeof(u32);
-       int total_bytes, wait_bytes;
-       bool need_wrap = false;
+       const unsigned int remain_usable = ring->effective_size - ring->emit;
+       const unsigned int bytes = num_dwords * sizeof(u32);
+       unsigned int need_wrap = 0;
+       unsigned int total_bytes;
+       u32 *cs;
 
        total_bytes = bytes + req->reserved_space;
+       GEM_BUG_ON(total_bytes > ring->effective_size);
 
-       if (unlikely(bytes > remain_usable)) {
-               /*
-                * Not enough space for the basic request. So need to flush
-                * out the remainder and then wait for base + reserved.
-                */
-               wait_bytes = remain_actual + total_bytes;
-               need_wrap = true;
-       } else if (unlikely(total_bytes > remain_usable)) {
-               /*
-                * The base request will fit but the reserved space
-                * falls off the end. So we don't need an immediate wrap
-                * and only need to effectively wait for the reserved
-                * size space from the start of ringbuffer.
-                */
-               wait_bytes = remain_actual + req->reserved_space;
-       } else {
-               /* No wrapping required, just waiting. */
-               wait_bytes = total_bytes;
+       if (unlikely(total_bytes > remain_usable)) {
+               const int remain_actual = ring->size - ring->emit;
+
+               if (bytes > remain_usable) {
+                       /*
+                        * Not enough space for the basic request. So need to
+                        * flush out the remainder and then wait for
+                        * base + reserved.
+                        */
+                       total_bytes += remain_actual;
+                       need_wrap = remain_actual | 1;
+               } else  {
+                       /*
+                        * The base request will fit but the reserved space
+                        * falls off the end. So we don't need an immediate
+                        * wrap and only need to effectively wait for the
+                        * reserved size from the start of ringbuffer.
+                        */
+                       total_bytes = req->reserved_space + remain_actual;
+               }
        }
 
-       if (wait_bytes > ring->space) {
-               int ret = wait_for_space(req, wait_bytes);
+       if (unlikely(total_bytes > ring->space)) {
+               int ret = wait_for_space(req, total_bytes);
                if (unlikely(ret))
-                       return ret;
+                       return ERR_PTR(ret);
        }
 
        if (unlikely(need_wrap)) {
-               GEM_BUG_ON(remain_actual > ring->space);
-               GEM_BUG_ON(ring->tail + remain_actual > ring->size);
+               need_wrap &= ~1;
+               GEM_BUG_ON(need_wrap > ring->space);
+               GEM_BUG_ON(ring->emit + need_wrap > ring->size);
 
                /* Fill the tail with MI_NOOP */
-               memset(ring->vaddr + ring->tail, 0, remain_actual);
-               ring->tail = 0;
-               ring->space -= remain_actual;
+               memset(ring->vaddr + ring->emit, 0, need_wrap);
+               ring->emit = 0;
+               ring->space -= need_wrap;
        }
 
+       GEM_BUG_ON(ring->emit > ring->size - bytes);
+       GEM_BUG_ON(ring->space < bytes);
+       cs = ring->vaddr + ring->emit;
+       GEM_DEBUG_EXEC(memset(cs, POISON_INUSE, bytes));
+       ring->emit += bytes;
        ring->space -= bytes;
-       GEM_BUG_ON(ring->space < 0);
-       return 0;
+
+       return cs;
 }
 
 /* Align the ring tail to a cacheline boundary */
 int intel_ring_cacheline_align(struct drm_i915_gem_request *req)
 {
-       struct intel_ring *ring = req->ring;
        int num_dwords =
-               (ring->tail & (CACHELINE_BYTES - 1)) / sizeof(uint32_t);
-       int ret;
+               (req->ring->emit & (CACHELINE_BYTES - 1)) / sizeof(uint32_t);
+       u32 *cs;
 
        if (num_dwords == 0)
                return 0;
 
        num_dwords = CACHELINE_BYTES / sizeof(uint32_t) - num_dwords;
-       ret = intel_ring_begin(req, num_dwords);
-       if (ret)
-               return ret;
+       cs = intel_ring_begin(req, num_dwords);
+       if (IS_ERR(cs))
+               return PTR_ERR(cs);
 
        while (num_dwords--)
-               intel_ring_emit(ring, MI_NOOP);
+               *cs++ = MI_NOOP;
 
-       intel_ring_advance(ring);
+       intel_ring_advance(req, cs);
 
        return 0;
 }
@@ -2318,11 +1805,11 @@ static void gen6_bsd_submit_request(struct drm_i915_gem_request *request)
        I915_WRITE64_FW(GEN6_BSD_RNCID, 0x0);
 
        /* Wait for the ring not to be idle, i.e. for it to wake up. */
-       if (intel_wait_for_register_fw(dev_priv,
-                                      GEN6_BSD_SLEEP_PSMI_CONTROL,
-                                      GEN6_BSD_SLEEP_INDICATOR,
-                                      0,
-                                      50))
+       if (__intel_wait_for_register_fw(dev_priv,
+                                        GEN6_BSD_SLEEP_PSMI_CONTROL,
+                                        GEN6_BSD_SLEEP_INDICATOR,
+                                        0,
+                                        1000, 0, NULL))
                DRM_ERROR("timed out waiting for the BSD ring to wake up\n");
 
        /* Now that the ring is fully powered up, update the tail */
@@ -2339,13 +1826,11 @@ static void gen6_bsd_submit_request(struct drm_i915_gem_request *request)
 
 static int gen6_bsd_ring_flush(struct drm_i915_gem_request *req, u32 mode)
 {
-       struct intel_ring *ring = req->ring;
-       uint32_t cmd;
-       int ret;
+       u32 cmd, *cs;
 
-       ret = intel_ring_begin(req, 4);
-       if (ret)
-               return ret;
+       cs = intel_ring_begin(req, 4);
+       if (IS_ERR(cs))
+               return PTR_ERR(cs);
 
        cmd = MI_FLUSH_DW;
        if (INTEL_GEN(req->i915) >= 8)
@@ -2367,16 +1852,16 @@ static int gen6_bsd_ring_flush(struct drm_i915_gem_request *req, u32 mode)
        if (mode & EMIT_INVALIDATE)
                cmd |= MI_INVALIDATE_TLB | MI_INVALIDATE_BSD;
 
-       intel_ring_emit(ring, cmd);
-       intel_ring_emit(ring, I915_GEM_HWS_SCRATCH_ADDR | MI_FLUSH_DW_USE_GTT);
+       *cs++ = cmd;
+       *cs++ = I915_GEM_HWS_SCRATCH_ADDR | MI_FLUSH_DW_USE_GTT;
        if (INTEL_GEN(req->i915) >= 8) {
-               intel_ring_emit(ring, 0); /* upper addr */
-               intel_ring_emit(ring, 0); /* value */
+               *cs++ = 0; /* upper addr */
+               *cs++ = 0; /* value */
        } else  {
-               intel_ring_emit(ring, 0);
-               intel_ring_emit(ring, MI_NOOP);
+               *cs++ = 0;
+               *cs++ = MI_NOOP;
        }
-       intel_ring_advance(ring);
+       intel_ring_advance(req, cs);
        return 0;
 }
 
@@ -2385,23 +1870,21 @@ gen8_emit_bb_start(struct drm_i915_gem_request *req,
                   u64 offset, u32 len,
                   unsigned int dispatch_flags)
 {
-       struct intel_ring *ring = req->ring;
        bool ppgtt = USES_PPGTT(req->i915) &&
                        !(dispatch_flags & I915_DISPATCH_SECURE);
-       int ret;
+       u32 *cs;
 
-       ret = intel_ring_begin(req, 4);
-       if (ret)
-               return ret;
+       cs = intel_ring_begin(req, 4);
+       if (IS_ERR(cs))
+               return PTR_ERR(cs);
 
        /* FIXME(BDW): Address space and security selectors. */
-       intel_ring_emit(ring, MI_BATCH_BUFFER_START_GEN8 | (ppgtt<<8) |
-                       (dispatch_flags & I915_DISPATCH_RS ?
-                        MI_BATCH_RESOURCE_STREAMER : 0));
-       intel_ring_emit(ring, lower_32_bits(offset));
-       intel_ring_emit(ring, upper_32_bits(offset));
-       intel_ring_emit(ring, MI_NOOP);
-       intel_ring_advance(ring);
+       *cs++ = MI_BATCH_BUFFER_START_GEN8 | (ppgtt << 8) | (dispatch_flags &
+               I915_DISPATCH_RS ? MI_BATCH_RESOURCE_STREAMER : 0);
+       *cs++ = lower_32_bits(offset);
+       *cs++ = upper_32_bits(offset);
+       *cs++ = MI_NOOP;
+       intel_ring_advance(req, cs);
 
        return 0;
 }
@@ -2411,22 +1894,19 @@ hsw_emit_bb_start(struct drm_i915_gem_request *req,
                  u64 offset, u32 len,
                  unsigned int dispatch_flags)
 {
-       struct intel_ring *ring = req->ring;
-       int ret;
+       u32 *cs;
 
-       ret = intel_ring_begin(req, 2);
-       if (ret)
-               return ret;
+       cs = intel_ring_begin(req, 2);
+       if (IS_ERR(cs))
+               return PTR_ERR(cs);
 
-       intel_ring_emit(ring,
-                       MI_BATCH_BUFFER_START |
-                       (dispatch_flags & I915_DISPATCH_SECURE ?
-                        0 : MI_BATCH_PPGTT_HSW | MI_BATCH_NON_SECURE_HSW) |
-                       (dispatch_flags & I915_DISPATCH_RS ?
-                        MI_BATCH_RESOURCE_STREAMER : 0));
+       *cs++ = MI_BATCH_BUFFER_START | (dispatch_flags & I915_DISPATCH_SECURE ?
+               0 : MI_BATCH_PPGTT_HSW | MI_BATCH_NON_SECURE_HSW) |
+               (dispatch_flags & I915_DISPATCH_RS ?
+               MI_BATCH_RESOURCE_STREAMER : 0);
        /* bit0-7 is the length on GEN6+ */
-       intel_ring_emit(ring, offset);
-       intel_ring_advance(ring);
+       *cs++ = offset;
+       intel_ring_advance(req, cs);
 
        return 0;
 }
@@ -2436,20 +1916,17 @@ gen6_emit_bb_start(struct drm_i915_gem_request *req,
                   u64 offset, u32 len,
                   unsigned int dispatch_flags)
 {
-       struct intel_ring *ring = req->ring;
-       int ret;
+       u32 *cs;
 
-       ret = intel_ring_begin(req, 2);
-       if (ret)
-               return ret;
+       cs = intel_ring_begin(req, 2);
+       if (IS_ERR(cs))
+               return PTR_ERR(cs);
 
-       intel_ring_emit(ring,
-                       MI_BATCH_BUFFER_START |
-                       (dispatch_flags & I915_DISPATCH_SECURE ?
-                        0 : MI_BATCH_NON_SECURE_I965));
+       *cs++ = MI_BATCH_BUFFER_START | (dispatch_flags & I915_DISPATCH_SECURE ?
+               0 : MI_BATCH_NON_SECURE_I965);
        /* bit0-7 is the length on GEN6+ */
-       intel_ring_emit(ring, offset);
-       intel_ring_advance(ring);
+       *cs++ = offset;
+       intel_ring_advance(req, cs);
 
        return 0;
 }
@@ -2458,13 +1935,11 @@ gen6_emit_bb_start(struct drm_i915_gem_request *req,
 
 static int gen6_ring_flush(struct drm_i915_gem_request *req, u32 mode)
 {
-       struct intel_ring *ring = req->ring;
-       uint32_t cmd;
-       int ret;
+       u32 cmd, *cs;
 
-       ret = intel_ring_begin(req, 4);
-       if (ret)
-               return ret;
+       cs = intel_ring_begin(req, 4);
+       if (IS_ERR(cs))
+               return PTR_ERR(cs);
 
        cmd = MI_FLUSH_DW;
        if (INTEL_GEN(req->i915) >= 8)
@@ -2485,17 +1960,16 @@ static int gen6_ring_flush(struct drm_i915_gem_request *req, u32 mode)
         */
        if (mode & EMIT_INVALIDATE)
                cmd |= MI_INVALIDATE_TLB;
-       intel_ring_emit(ring, cmd);
-       intel_ring_emit(ring,
-                       I915_GEM_HWS_SCRATCH_ADDR | MI_FLUSH_DW_USE_GTT);
+       *cs++ = cmd;
+       *cs++ = I915_GEM_HWS_SCRATCH_ADDR | MI_FLUSH_DW_USE_GTT;
        if (INTEL_GEN(req->i915) >= 8) {
-               intel_ring_emit(ring, 0); /* upper addr */
-               intel_ring_emit(ring, 0); /* value */
+               *cs++ = 0; /* upper addr */
+               *cs++ = 0; /* value */
        } else  {
-               intel_ring_emit(ring, 0);
-               intel_ring_emit(ring, MI_NOOP);
+               *cs++ = 0;
+               *cs++ = MI_NOOP;
        }
-       intel_ring_advance(ring);
+       intel_ring_advance(req, cs);
 
        return 0;
 }
@@ -2635,6 +2109,16 @@ static void intel_ring_init_irq(struct drm_i915_private *dev_priv,
        }
 }
 
+static void i9xx_set_default_submission(struct intel_engine_cs *engine)
+{
+       engine->submit_request = i9xx_submit_request;
+}
+
+static void gen6_bsd_set_default_submission(struct intel_engine_cs *engine)
+{
+       engine->submit_request = gen6_bsd_submit_request;
+}
+
 static void intel_ring_default_vfuncs(struct drm_i915_private *dev_priv,
                                      struct intel_engine_cs *engine)
 {
@@ -2656,7 +2140,7 @@ static void intel_ring_default_vfuncs(struct drm_i915_private *dev_priv,
 
                engine->emit_breadcrumb = gen6_sema_emit_breadcrumb;
 
-               num_rings = hweight32(INTEL_INFO(dev_priv)->ring_mask) - 1;
+               num_rings = INTEL_INFO(dev_priv)->num_rings - 1;
                if (INTEL_GEN(dev_priv) >= 8) {
                        engine->emit_breadcrumb_sz += num_rings * 6;
                } else {
@@ -2665,7 +2149,8 @@ static void intel_ring_default_vfuncs(struct drm_i915_private *dev_priv,
                                engine->emit_breadcrumb_sz++;
                }
        }
-       engine->submit_request = i9xx_submit_request;
+
+       engine->set_default_submission = i9xx_set_default_submission;
 
        if (INTEL_GEN(dev_priv) >= 8)
                engine->emit_bb_start = gen8_emit_bb_start;
@@ -2699,9 +2184,8 @@ int intel_init_render_ring_buffer(struct intel_engine_cs *engine)
 
                        engine->semaphore.signal = gen8_rcs_signal;
 
-                       num_rings =
-                               hweight32(INTEL_INFO(dev_priv)->ring_mask) - 1;
-                       engine->emit_breadcrumb_sz += num_rings * 6;
+                       num_rings = INTEL_INFO(dev_priv)->num_rings - 1;
+                       engine->emit_breadcrumb_sz += num_rings * 8;
                }
        } else if (INTEL_GEN(dev_priv) >= 6) {
                engine->init_context = intel_rcs_ctx_init;
@@ -2750,7 +2234,7 @@ int intel_init_bsd_ring_buffer(struct intel_engine_cs *engine)
        if (INTEL_GEN(dev_priv) >= 6) {
                /* gen6 bsd needs a special wa for tail updates */
                if (IS_GEN6(dev_priv))
-                       engine->submit_request = gen6_bsd_submit_request;
+                       engine->set_default_submission = gen6_bsd_set_default_submission;
                engine->emit_flush = gen6_bsd_ring_flush;
                if (INTEL_GEN(dev_priv) < 8)
                        engine->irq_enable_mask = GT_BSD_USER_INTERRUPT;
@@ -2766,20 +2250,6 @@ int intel_init_bsd_ring_buffer(struct intel_engine_cs *engine)
        return intel_init_ring_buffer(engine);
 }
 
-/**
- * Initialize the second BSD ring (eg. Broadwell GT3, Skylake GT3)
- */
-int intel_init_bsd2_ring_buffer(struct intel_engine_cs *engine)
-{
-       struct drm_i915_private *dev_priv = engine->i915;
-
-       intel_ring_default_vfuncs(dev_priv, engine);
-
-       engine->emit_flush = gen6_bsd_ring_flush;
-
-       return intel_init_ring_buffer(engine);
-}
-
 int intel_init_blt_ring_buffer(struct intel_engine_cs *engine)
 {
        struct drm_i915_private *dev_priv = engine->i915;