[Intel-gfx] [PATCH 03/10] drm/i915: Grab crtc->mutex in intel_fbc_work_fn()

[ville.syrjala at linux.intel.com]

From: Ville Syrjälä <ville.syrjala at linux.intel.com>

Make the FBC code a bit less racy by grabbing crtc->mutex
in intel_fbc_work_fn() when we go digging through the crtc
state.

Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
 drivers/gpu/drm/i915/intel_pm.c | 5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/i915/intel_pm.c b/drivers/gpu/drm/i915/intel_pm.c
index 8780b87..dc65bb4 100644
--- a/drivers/gpu/drm/i915/intel_pm.c
+++ b/drivers/gpu/drm/i915/intel_pm.c
@@ -333,9 +333,12 @@ static void intel_fbc_work_fn(struct work_struct *__work)
 	struct intel_fbc_work *work =
 		container_of(to_delayed_work(__work),
 			     struct intel_fbc_work, work);
+	struct drm_crtc *crtc = work->crtc;
 	struct drm_device *dev = work->crtc->dev;
 	struct drm_i915_private *dev_priv = dev->dev_private;
 
+	mutex_lock(&crtc->mutex);
+
 	mutex_lock(&dev->struct_mutex);
 	if (work == dev_priv->fbc.fbc_work) {
 		/* Double check that we haven't switched fb without cancelling
@@ -347,6 +350,8 @@ static void intel_fbc_work_fn(struct work_struct *__work)
 	}
 	mutex_unlock(&dev->struct_mutex);
 
+	mutex_unlock(&crtc->mutex);
+
 	drm_framebuffer_reference(work->fb);
 
 	kfree(work);
-- 
1.8.1.5