[Intel-gfx] [PATCH 2/9] drm/i915: Filter out no-op frontbuffer tracking flushes

[Daniel Vetter]

Paulo noticed that the fbc frontbuffer tracking flush callback
occasionally gets a call without any bit set. This can happen when we
have to filter flush calls due to e.g. gpu rendering. Filter these
out.

Reported-by: Paulo Zanoni <przanoni at gmail.com>
Cc: Paulo Zanoni <przanoni at gmail.com>
Signed-off-by: Daniel Vetter <daniel.vetter at intel.com>
---
 drivers/gpu/drm/i915/intel_frontbuffer.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_frontbuffer.c b/drivers/gpu/drm/i915/intel_frontbuffer.c
index 2a1611a7ce1d..899b6112bbe0 100644
--- a/drivers/gpu/drm/i915/intel_frontbuffer.c
+++ b/drivers/gpu/drm/i915/intel_frontbuffer.c
@@ -179,6 +179,9 @@ void intel_frontbuffer_flush(struct drm_device *dev,
 	frontbuffer_bits &= ~dev_priv->fb_tracking.busy_bits;
 	mutex_unlock(&dev_priv->fb_tracking.lock);
 
+	if (!frontbuffer_bits)
+		return;
+
 	intel_mark_fb_busy(dev, frontbuffer_bits, NULL);
 
 	intel_edp_drrs_flush(dev, frontbuffer_bits);
-- 
2.1.0