drm/i915: don't enable FBC when pixel rate exceeds 95% on HSW/BDW

BSpec says we shouldn't enable FBC on HSW/BDW when the pipe pixel rate
exceeds 95% of the core display clock.

v2:
  - HSW also needs the WA (Ville).
  - Add the WA name (Ville).
  - Use the current cdclk (Ville).

Signed-off-by: Paulo Zanoni <paulo.r.zanoni@intel.com>
Reviewed-by: Ville Syrjälä <ville.syrjala@linux.intel.com>
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

diff --git a/drivers/gpu/drm/i915/i915_drv.h b/drivers/gpu/drm/i915/i915_drv.h
index ffd4ab111957fca30b571fcfdaceb7594ca3498f..e5242c0ce4f113432227167872f5ad039433baae 100644 (file)
--- a/drivers/gpu/drm/i915/i915_drv.h
+++ b/drivers/gpu/drm/i915/i915_drv.h
@@ -949,6 +949,7 @@ struct i915_fbc {
                FBC_ROTATION, /* rotation is not supported */
                FBC_IN_DBG_MASTER, /* kernel debugger is active */
                FBC_BAD_STRIDE, /* stride is not supported */
+               FBC_PIXEL_RATE, /* pixel rate is too big */
        } no_fbc_reason;
 
        bool (*fbc_enabled)(struct drm_i915_private *dev_priv);

diff --git a/drivers/gpu/drm/i915/intel_fbc.c b/drivers/gpu/drm/i915/intel_fbc.c
index 69726a7ed0d0f1ad8268481e24a504376a84d431..1c4536ad4de984577b35d72701b0bd281d267858 100644 (file)
--- a/drivers/gpu/drm/i915/intel_fbc.c
+++ b/drivers/gpu/drm/i915/intel_fbc.c
@@ -482,6 +482,8 @@ const char *intel_no_fbc_reason_str(enum no_fbc_reason reason)
                return "Kernel debugger is active";
        case FBC_BAD_STRIDE:
                return "framebuffer stride not supported";
+       case FBC_PIXEL_RATE:
+               return "pixel rate is too big";
        default:
                MISSING_CASE(reason);
                return "unknown reason";
@@ -828,6 +830,14 @@ static void __intel_fbc_update(struct drm_i915_private *dev_priv)
                goto out_disable;
        }
 
+       /* WaFbcExceedCdClockThreshold:hsw,bdw */
+       if ((IS_HASWELL(dev_priv) || IS_BROADWELL(dev_priv)) &&
+           ilk_pipe_pixel_rate(intel_crtc->config) >=
+           dev_priv->cdclk_freq * 95 / 100) {
+               set_no_fbc_reason(dev_priv, FBC_PIXEL_RATE);
+               goto out_disable;
+       }
+
        if (intel_fbc_setup_cfb(dev_priv, obj->base.size,
                                drm_format_plane_cpp(fb->pixel_format, 0))) {
                set_no_fbc_reason(dev_priv, FBC_STOLEN_TOO_SMALL);