[Intel-gfx] [PATCH 5/9] drm: Have the vblank counter account for the time between vblank irq disable and drm_vblank_off()
ville.syrjala at linux.intel.com
ville.syrjala at linux.intel.com
Mon May 26 13:46:28 CEST 2014
From: Ville Syrjälä <ville.syrjala at linux.intel.com>
If the vblank irq has already been disabled (via the disable timer) when
we call drm_vblank_off() sample the counter and timestamp one last time.
This will make the sure that the user space visible counter will account
for time between vblank irq disable and drm_vblank_off().
Signed-off-by: Ville Syrjälä <ville.syrjala at linux.intel.com>
---
drivers/gpu/drm/drm_irq.c | 13 +++++++++++++
1 file changed, 13 insertions(+)
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
index e12cf69..bb64f0f 100644
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -140,6 +140,19 @@ static void vblank_disable_and_save(struct drm_device *dev, int crtc)
*/
spin_lock_irqsave(&dev->vblank_time_lock, irqflags);
+ /*
+ * If the vblank interrupt was already disbled update the count
+ * and timestamp to maintain the appearance that the counter
+ * has been ticking all along until this time. This makes the
+ * count account for the entire time between drm_vblank_on() and
+ * drm_vblank_off().
+ */
+ if (!dev->vblank[crtc].enabled) {
+ drm_update_vblank_count(dev, crtc);
+ spin_unlock_irqrestore(&dev->vblank_time_lock, irqflags);
+ return;
+ }
+
dev->driver->disable_vblank(dev, crtc);
dev->vblank[crtc].enabled = false;
--
1.8.5.5
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