[PATCH 2/3] drm: Warn if vblank state has become inconsistent.

[christopher.halse.rogers at canonical.com]

From: Christopher James Halse Rogers <christopher.halse.rogers at canonical.com>

After emitting all the waiting vblank events no-one should hold
a vblank reference.  Emit a warning if this is not the case.

Signed-off-by: Christopher James Halse Rogers <christopher.halse.rogers at canonical.com>
---
 drivers/gpu/drm/drm_irq.c |    1 +
 1 files changed, 1 insertions(+), 0 deletions(-)

diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
index a1f12cb..72407fa 100644
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -960,6 +960,7 @@ void drm_vblank_off(struct drm_device *dev, int crtc)
 						 e->event.sequence);
 	}
 
+	WARN_ON(atomic_read(&dev->vblank_refcount[crtc]) != 0);
 	spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
 }
 EXPORT_SYMBOL(drm_vblank_off);
-- 
1.7.4.1