From: Ville Syrjälä ville.syrjala@linux.intel.com
Pontential infinite loops in the vblank code are a bad idea. Add some limits.
Signed-off-by: Ville Syrjälä ville.syrjala@linux.intel.com --- 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; }