diff options
Diffstat (limited to 'drivers/gpu/drm/drm_irq.c')
| -rw-r--r-- | drivers/gpu/drm/drm_irq.c | 12 |
1 files changed, 12 insertions, 0 deletions
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c index 1f86f6c6ecc6..fc1525a499d9 100644 --- a/drivers/gpu/drm/drm_irq.c +++ b/drivers/gpu/drm/drm_irq.c @@ -1095,6 +1095,18 @@ void drm_vblank_on(struct drm_device *dev, int crtc) atomic_dec(&dev->vblank[crtc].refcount); dev->vblank[crtc].inmodeset = 0; } + + /* + * sample the current counter to avoid random jumps + * when drm_vblank_enable() applies the diff + * + * -1 to make sure user will never see the same + * vblank counter value before and after a modeset + */ + dev->vblank[crtc].last = + (dev->driver->get_vblank_counter(dev, crtc) - 1) & + dev->max_vblank_count; + /* re-enable interrupts if there's are users left */ if (atomic_read(&dev->vblank[crtc].refcount) != 0) WARN_ON(drm_vblank_enable(dev, crtc)); |