drm/i915: make the blitter report buffer modifications to the FBC unit
Without this change, blits to the front buffer won't invalidate FBC
state, causing us to scan out stale data. Make sure we update these
bits on every FBC enable, since they may get clobbered if we shut off
the display.
References: https://bugzilla.kernel.org/show_bug.cgi?id=26932
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
diff --git a/drivers/gpu/drm/i915/intel_display.c b/drivers/gpu/drm/i915/intel_display.c
index d2ef1c2..d7f237d 100644
--- a/drivers/gpu/drm/i915/intel_display.c
+++ b/drivers/gpu/drm/i915/intel_display.c
@@ -1213,6 +1213,26 @@
return I915_READ(DPFC_CONTROL) & DPFC_CTL_EN;
}
+static void sandybridge_blit_fbc_update(struct drm_device *dev)
+{
+ struct drm_i915_private *dev_priv = dev->dev_private;
+ u32 blt_ecoskpd;
+
+ /* Make sure blitter notifies FBC of writes */
+ __gen6_force_wake_get(dev_priv);
+ blt_ecoskpd = I915_READ(GEN6_BLITTER_ECOSKPD);
+ blt_ecoskpd |= GEN6_BLITTER_FBC_NOTIFY <<
+ GEN6_BLITTER_LOCK_SHIFT;
+ I915_WRITE(GEN6_BLITTER_ECOSKPD, blt_ecoskpd);
+ blt_ecoskpd |= GEN6_BLITTER_FBC_NOTIFY;
+ I915_WRITE(GEN6_BLITTER_ECOSKPD, blt_ecoskpd);
+ blt_ecoskpd &= ~(GEN6_BLITTER_FBC_NOTIFY <<
+ GEN6_BLITTER_LOCK_SHIFT);
+ I915_WRITE(GEN6_BLITTER_ECOSKPD, blt_ecoskpd);
+ POSTING_READ(GEN6_BLITTER_ECOSKPD);
+ __gen6_force_wake_put(dev_priv);
+}
+
static void ironlake_enable_fbc(struct drm_crtc *crtc, unsigned long interval)
{
struct drm_device *dev = crtc->dev;
@@ -1266,6 +1286,7 @@
I915_WRITE(SNB_DPFC_CTL_SA,
SNB_CPU_FENCE_ENABLE | dev_priv->cfb_fence);
I915_WRITE(DPFC_CPU_FENCE_OFFSET, crtc->y);
+ sandybridge_blit_fbc_update(dev);
}
DRM_DEBUG_KMS("enabled fbc on plane %d\n", intel_crtc->plane);