From: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
Pontential infinite loops in the vblank code are a bad idea. Add some
limits.
Signed-off-by: Ville Syrjälä <ville.syrjala@xxxxxxxxxxxxxxx>
---
drivers/gpu/drm/drm_irq.c | 6 ++++--
1 file changed, 4 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
index 0353224..93fe582 100644
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -127,6 +127,7 @@ static void drm_update_vblank_count(struct drm_device *dev, unsigned int pipe,
u32 cur_vblank, diff;
bool rc;
struct timeval t_vblank;
+ int count = DRM_TIMESTAMP_MAXRETRIES;
/*
* Interrupts were disabled prior to this call, so deal with counter
@@ -143,7 +144,7 @@ static void drm_update_vblank_count(struct drm_device *dev, unsigned int pipe,
do {
cur_vblank = dev->driver->get_vblank_counter(dev, pipe);
rc = drm_get_last_vbltimestamp(dev, pipe, &t_vblank, flags);
- } while (cur_vblank != dev->driver->get_vblank_counter(dev, pipe));
+ } while (cur_vblank != dev->driver->get_vblank_counter(dev, pipe) && --count > 0);
/* Deal with counter wrap */
diff = cur_vblank - vblank->last;
@@ -914,6 +915,7 @@ u32 drm_vblank_count_and_time(struct drm_device *dev, unsigned int pipe,
struct timeval *vblanktime)
{
struct drm_vblank_crtc *vblank = &dev->vblank[pipe];
+ int count = DRM_TIMESTAMP_MAXRETRIES;
u32 cur_vblank;
if (WARN_ON(pipe >= dev->num_crtcs))
@@ -929,7 +931,7 @@ u32 drm_vblank_count_and_time(struct drm_device *dev, unsigned int pipe,
smp_rmb();
*vblanktime = vblanktimestamp(dev, pipe, cur_vblank);
smp_rmb();
- } while (cur_vblank != vblank->count);
+ } while (cur_vblank != vblank->count && --count > 0);
return cur_vblank;
}
--
2.4.6
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