From c4cc383915549cf14f027f374904e30c13653dac Mon Sep 17 00:00:00 2001 From: Mario Kleiner Date: Mon, 21 Feb 2011 05:42:00 +0100 Subject: [PATCH] drm/vblank: Use abs64(diff_ns) for s64 diff_ns instead of abs(diff_ns) 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 Signed-off-by: Dave Airlie --- drivers/gpu/drm/drm_irq.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-) diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c index 3dadfa2a8528..6d2d4faf8678 100644 --- a/drivers/gpu/drm/drm_irq.c +++ b/drivers/gpu/drm/drm_irq.c @@ -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(); -- 2.39.2