From: Matthew Brost Date: Thu, 8 Jul 2021 16:20:53 +0000 (-0700) Subject: drm/i915/guc: Add stall timer to non blocking CTB send function X-Git-Tag: libata-5.15-2021-09-05~42^2~11^2~146 X-Git-Url: https://git.kernel.dk/?a=commitdiff_plain;h=b43b9950486eb9b229493fc91cdabbbb4d07cfbc;p=linux-2.6-block.git drm/i915/guc: Add stall timer to non blocking CTB send function Implement a stall timer which fails H2G CTBs once a period of time with no forward progress is reached to prevent deadlock. v2: (Michal) - Improve error message in ct_deadlock() - Set broken when ct_deadlock() returns true - Return -EPIPE on ct_deadlock() v3: (Michal) - Add ms to stall timer comment (Matthew) - Move broken check to intel_guc_ct_send() Signed-off-by: John Harrison Signed-off-by: Daniele Ceraolo Spurio Signed-off-by: Matthew Brost Reviewed-by: John Harrison Signed-off-by: John Harrison Link: https://patchwork.freedesktop.org/patch/msgid/20210708162055.129996-6-matthew.brost@intel.com --- diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c index 3d6cba8d91ad..db3e85b89573 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.c @@ -4,6 +4,9 @@ */ #include +#include +#include +#include #include "i915_drv.h" #include "intel_guc_ct.h" @@ -316,6 +319,7 @@ int intel_guc_ct_enable(struct intel_guc_ct *ct) goto err_deregister; ct->enabled = true; + ct->stall_time = KTIME_MAX; return 0; @@ -389,9 +393,6 @@ static int ct_write(struct intel_guc_ct *ct, u32 *cmds = ctb->cmds; unsigned int i; - if (unlikely(ctb->broken)) - return -EPIPE; - if (unlikely(desc->status)) goto corrupted; @@ -505,6 +506,25 @@ static int wait_for_ct_request_update(struct ct_request *req, u32 *status) return err; } +#define GUC_CTB_TIMEOUT_MS 1500 +static inline bool ct_deadlocked(struct intel_guc_ct *ct) +{ + long timeout = GUC_CTB_TIMEOUT_MS; + bool ret = ktime_ms_delta(ktime_get(), ct->stall_time) > timeout; + + if (unlikely(ret)) { + struct guc_ct_buffer_desc *send = ct->ctbs.send.desc; + struct guc_ct_buffer_desc *recv = ct->ctbs.send.desc; + + CT_ERROR(ct, "Communication stalled for %lld ms, desc status=%#x,%#x\n", + ktime_ms_delta(ktime_get(), ct->stall_time), + send->status, recv->status); + ct->ctbs.send.broken = true; + } + + return ret; +} + static inline bool h2g_has_room(struct intel_guc_ct_buffer *ctb, u32 len_dw) { struct guc_ct_buffer_desc *desc = ctb->desc; @@ -516,6 +536,26 @@ static inline bool h2g_has_room(struct intel_guc_ct_buffer *ctb, u32 len_dw) return space >= len_dw; } +static int has_room_nb(struct intel_guc_ct *ct, u32 len_dw) +{ + struct intel_guc_ct_buffer *ctb = &ct->ctbs.send; + + lockdep_assert_held(&ct->ctbs.send.lock); + + if (unlikely(!h2g_has_room(ctb, len_dw))) { + if (ct->stall_time == KTIME_MAX) + ct->stall_time = ktime_get(); + + if (unlikely(ct_deadlocked(ct))) + return -EPIPE; + else + return -EBUSY; + } + + ct->stall_time = KTIME_MAX; + return 0; +} + static int ct_send_nb(struct intel_guc_ct *ct, const u32 *action, u32 len, @@ -528,11 +568,9 @@ static int ct_send_nb(struct intel_guc_ct *ct, spin_lock_irqsave(&ctb->lock, spin_flags); - ret = h2g_has_room(ctb, len + GUC_CTB_HDR_LEN); - if (unlikely(!ret)) { - ret = -EBUSY; + ret = has_room_nb(ct, len + GUC_CTB_HDR_LEN); + if (unlikely(ret)) goto out; - } fence = ct_get_next_fence(ct); ret = ct_write(ct, action, len, fence, flags); @@ -575,8 +613,13 @@ static int ct_send(struct intel_guc_ct *ct, retry: spin_lock_irqsave(&ctb->lock, flags); if (unlikely(!h2g_has_room(ctb, len + GUC_CTB_HDR_LEN))) { + if (ct->stall_time == KTIME_MAX) + ct->stall_time = ktime_get(); spin_unlock_irqrestore(&ctb->lock, flags); + if (unlikely(ct_deadlocked(ct))) + return -EPIPE; + if (msleep_interruptible(sleep_period_ms)) return -EINTR; sleep_period_ms = sleep_period_ms << 1; @@ -584,6 +627,8 @@ retry: goto retry; } + ct->stall_time = KTIME_MAX; + fence = ct_get_next_fence(ct); request.fence = fence; request.status = 0; @@ -646,6 +691,9 @@ int intel_guc_ct_send(struct intel_guc_ct *ct, const u32 *action, u32 len, return -ENODEV; } + if (unlikely(ct->ctbs.send.broken)) + return -EPIPE; + if (flags & INTEL_GUC_CT_SEND_NB) return ct_send_nb(ct, action, len, flags); diff --git a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h index 5bb8bef024c8..bee03794c1eb 100644 --- a/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h +++ b/drivers/gpu/drm/i915/gt/uc/intel_guc_ct.h @@ -9,6 +9,7 @@ #include #include #include +#include #include "intel_guc_fwif.h" @@ -68,6 +69,9 @@ struct intel_guc_ct { struct list_head incoming; /* incoming requests */ struct work_struct worker; /* handler for incoming requests */ } requests; + + /** @stall_time: time of first time a CTB submission is stalled */ + ktime_t stall_time; }; void intel_guc_ct_init_early(struct intel_guc_ct *ct);