[PATCH 6/6] drm/i915: Sanitize drm crtc vblank counter after DC reset frame count.

[Rodrigo Vivi]

DC state reset the frame counter that is a read-only register.

So, besides blocking DC state on vblank let's restore the
drm crtc vblank counter to a place we know it is reliable.

Signed-off-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
---
 drivers/gpu/drm/i915/i915_irq.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_irq.c b/drivers/gpu/drm/i915/i915_irq.c
index 4efe20c..82d6896 100644
--- a/drivers/gpu/drm/i915/i915_irq.c
+++ b/drivers/gpu/drm/i915/i915_irq.c
@@ -2759,7 +2759,9 @@ static int gen8_enable_vblank(struct drm_device *dev, unsigned int pipe)
 static void gen9_prepare_vblank(struct drm_device *dev, unsigned int pipe)
 {
 	struct drm_i915_private *dev_priv = to_i915(dev);
+	struct drm_crtc *crtc = dev_priv->pipe_to_crtc_mapping[pipe];
 	intel_display_power_get(dev_priv, POWER_DOMAIN_VBLANK);
+	drm_crtc_vblank_sanitize_counter(crtc);
 }
 
 static void gen9_unprepare_vblank(struct drm_device *dev, unsigned int pipe)
-- 
2.4.3