diff options
| author | Mario Kleiner <mario.kleiner@tuebingen.mpg.de> | 2011-02-21 05:42:01 +0100 |
|---|---|---|
| committer | Dave Airlie <airlied@redhat.com> | 2011-02-23 10:08:46 +1000 |
| commit | bc21512835a72bc1eab7abd7d8a1bff0435591d7 (patch) | |
| tree | 015b9212d6fbd176dcbe141d5d96ee30d4bf1a76 | |
| parent | c4cc383915549cf14f027f374904e30c13653dac (diff) | |
drm/vblank: Use memory barriers optimized for atomic_t instead of generics.
Documentation/atomic_ops.txt tells us that there are memory
barriers optimized for atomic_inc and other atomic_t ops.
Use these instead of smp_wmb(), and also to make the required
memory barriers around vblank counter increments more explicit.
Signed-off-by: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>
Signed-off-by: Dave Airlie <airlied@redhat.com>
| -rw-r--r-- | drivers/gpu/drm/drm_irq.c | 10 |
1 files changed, 7 insertions, 3 deletions
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c index 6d2d4faf8678..22f3bf5ecbd2 100644 --- a/drivers/gpu/drm/drm_irq.c +++ b/drivers/gpu/drm/drm_irq.c @@ -164,8 +164,10 @@ static void vblank_disable_and_save(struct drm_device *dev, int crtc) * available. In that case we can't account for this and just * hope for the best. */ - if ((vblrc > 0) && (abs64(diff_ns) > 1000000)) + if ((vblrc > 0) && (abs64(diff_ns) > 1000000)) { atomic_inc(&dev->_vblank_count[crtc]); + smp_mb__after_atomic_inc(); + } /* Invalidate all timestamps while vblank irq's are off. */ clear_vblank_timestamps(dev, crtc); @@ -858,10 +860,11 @@ static void drm_update_vblank_count(struct drm_device *dev, int crtc) if (rc) { tslot = atomic_read(&dev->_vblank_count[crtc]) + diff; vblanktimestamp(dev, crtc, tslot) = t_vblank; - smp_wmb(); } + smp_mb__before_atomic_inc(); atomic_add(diff, &dev->_vblank_count[crtc]); + smp_mb__after_atomic_inc(); } /** @@ -1296,12 +1299,13 @@ bool drm_handle_vblank(struct drm_device *dev, int crtc) if (abs64(diff_ns) > DRM_REDUNDANT_VBLIRQ_THRESH_NS) { /* Store new timestamp in ringbuffer. */ vblanktimestamp(dev, crtc, vblcount + 1) = tvblank; - smp_wmb(); /* Increment cooked vblank count. This also atomically commits * the timestamp computed above. */ + smp_mb__before_atomic_inc(); atomic_inc(&dev->_vblank_count[crtc]); + smp_mb__after_atomic_inc(); } else { DRM_DEBUG("crtc %d: Redundant vblirq ignored. diff_ns = %d\n", crtc, (int) diff_ns); |