drm/i915: Implement display w/a 1140 for glk/cnl

Display w/a #1140 tells us we have to program the transition
watermark to the minimum value on glk/cnl. Let's do that.

Signed-off-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Reviewed-by: Rodrigo Vivi <rodrigo.vivi@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20200228203552.30273-4-ville.syrjala@linux.intel.com

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 3501c33e75a87b2333899d9877bb1568cb1ccd59..8375054ba27d92b72f6b03a0e15f2703b5befdb5 100644 (file)
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -5120,8 +5120,7 @@ static void skl_compute_transition_wm(const struct intel_crtc_state *crtc_state,
 {
        struct drm_device *dev = crtc_state->uapi.crtc->dev;
        const struct drm_i915_private *dev_priv = to_i915(dev);
-       u16 trans_min, trans_y_tile_min;
-       const u16 trans_amount = 10; /* This is configurable amount */
+       u16 trans_min, trans_amount, trans_y_tile_min;
        u16 wm0_sel_res_b, trans_offset_b, res_blocks;
 
        /* Transition WM don't make any sense if ipc is disabled */
@@ -5135,9 +5134,16 @@ static void skl_compute_transition_wm(const struct intel_crtc_state *crtc_state,
        if (IS_GEN9_BC(dev_priv) || IS_BROXTON(dev_priv))
                return;
 
-       trans_min = 14;
        if (INTEL_GEN(dev_priv) >= 11)
                trans_min = 4;
+       else
+               trans_min = 14;
+
+       /* Display WA #1140: glk,cnl */
+       if (IS_CANNONLAKE(dev_priv) || IS_GEMINILAKE(dev_priv))
+               trans_amount = 0;
+       else
+               trans_amount = 10; /* This is configurable amount */
 
        trans_offset_b = trans_min + trans_amount;
 
@@ -5164,7 +5170,6 @@ static void skl_compute_transition_wm(const struct intel_crtc_state *crtc_state,
                /* WA BUG:1938466 add one block for non y-tile planes */
                if (IS_CNL_REVID(dev_priv, CNL_REVID_A0, CNL_REVID_A0))
                        res_blocks += 1;
-
        }
 
        /*