diff options
| author | Michel Dänzer <michel@tungstengraphics.com> | 2008-06-03 11:28:09 +0200 |
|---|---|---|
| committer | Michel Dänzer <michel@tungstengraphics.com> | 2008-06-03 11:28:09 +0200 |
| commit | d1dcb2b32e0c51d7cbcaa2ba1e0544452cf8f47b (patch) | |
| tree | 4b2491f2ce700aa7243c37da209a8366d881f95d | |
| parent | 0144ebeb8a713b1420d35004075037cd4b0495a1 (diff) | |
vblank: Special-case driver vblank counter going back by 1.
Turns out the radeon driver is affected by the same problem that prompted i915
to revert to less useful counter flipping at the end of the vblank interval. In
the long term, we can hopefully implement more reliable methods to achieve
counter flipping at the beginning of vblank, but otherwise this should be an
acceptable workaround.
| -rw-r--r-- | linux-core/drm_irq.c | 13 |
1 files changed, 10 insertions, 3 deletions
diff --git a/linux-core/drm_irq.c b/linux-core/drm_irq.c index e2f106e4..ccb3ca89 100644 --- a/linux-core/drm_irq.c +++ b/linux-core/drm_irq.c @@ -360,9 +360,16 @@ void drm_update_vblank_count(struct drm_device *dev, int crtc) cur_vblank = dev->driver->get_vblank_counter(dev, crtc); spin_lock_irqsave(&dev->vbl_lock, irqflags); if (cur_vblank < dev->last_vblank[crtc]) { - diff = dev->max_vblank_count - - dev->last_vblank[crtc]; - diff += cur_vblank; + if (cur_vblank == dev->last_vblank[crtc] - 1) { + diff = 0; + } else { + diff = dev->max_vblank_count - + dev->last_vblank[crtc]; + diff += cur_vblank; + } + + DRM_DEBUG("last_vblank[%d]=0x%x, cur_vblank=0x%x => diff=0x%x\n", + crtc, dev->last_vblank[crtc], cur_vblank, diff); } else { diff = cur_vblank - dev->last_vblank[crtc]; } |