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drm/vblank: Use abs64(diff_ns) for s64 diff_ns instead of abs(diff_ns)

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Use of abs() wrongly wrapped diff_ns to 32 bit, which gives a 1/4000
probability of a missed vblank increment at each vblank irq reenable
if the kms driver doesn't support high precision vblank timestamping.
Not a big deal in practice, but let's make it nice.

Signed-off-by: Mario Kleiner <mario.kleiner@tuebingen.mpg.de>
Signed-off-by: Dave Airlie <airlied@redhat.com>
This commit is contained in:
Mario Kleiner 2011-02-21 05:42:00 +01:00 committed by Dave Airlie
parent e40b6fc837
commit c4cc383915
1 changed files with 2 additions and 2 deletions
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4
drivers/gpu/drm/drm_irq.c
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@ -164,7 +164,7 @@ 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) && (abs(diff_ns) > 1000000))
if ((vblrc > 0) && (abs64(diff_ns) > 1000000))
atomic_inc(&dev->_vblank_count[crtc]);
/* Invalidate all timestamps while vblank irq's are off. */
@ -1293,7 +1293,7 @@ bool drm_handle_vblank(struct drm_device *dev, int crtc)
* e.g., due to spurious vblank interrupts. We need to
* ignore those for accounting.
*/
if (abs(diff_ns) > DRM_REDUNDANT_VBLIRQ_THRESH_NS) {
if (abs64(diff_ns) > DRM_REDUNDANT_VBLIRQ_THRESH_NS) {
/* Store new timestamp in ringbuffer. */
vblanktimestamp(dev, crtc, vblcount + 1) = tvblank;
smp_wmb();