[041/146] drm: Send pending vblank events before disabling vblank.

Greg KH
2011-06-01T09:24:17Z

From: Christopher James Halse Rogers <christopher.halse.rogers@canonical.com>

commit 498548ec69c6897fe4376b2ca90758762fa0b817 upstream.

This is the least-bad behaviour. It means that we signal the
vblank event before it actually happens, but since we're disabling
vblanks there's no guarantee that it will *ever* happen otherwise.

This prevents GL applications which use WaitMSC from hanging
indefinitely.

Signed-off-by: Christopher James Halse Rogers <christopher.halse.rogers@canonical.com>
Signed-off-by: Dave Airlie <airlied@redhat.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
drivers/gpu/drm/drm_irq.c | 23 +++++++++++++++++++++++
1 file changed, 23 insertions(+)

--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -942,11 +942,34 @@ EXPORT_SYMBOL(drm_vblank_put);

void drm_vblank_off(struct drm_device *dev, int crtc)
{
+ struct drm_pending_vblank_event *e, *t;
+ struct timeval now;
unsigned long irqflags;
+ unsigned int seq;

spin_lock_irqsave(&dev->vbl_lock, irqflags);
vblank_disable_and_save(dev, crtc);
DRM_WAKEUP(&dev->vbl_queue[crtc]);
+
+ /* Send any queued vblank events, lest the natives grow disquiet */
+ seq = drm_vblank_count_and_time(dev, crtc, &now);
+ list_for_each_entry_safe(e, t, &dev->vblank_event_list, base.link) {
+ if (e->pipe != crtc)
+ continue;
+ DRM_DEBUG("Sending premature vblank event on disable: \
+ wanted %d, current %d\n",
+ e->event.sequence, seq);
+
+ e->event.sequence = seq;
+ e->event.tv_sec = now.tv_sec;
+ e->event.tv_usec = now.tv_usec;
+ drm_vblank_put(dev, e->pipe);
+ list_move_tail(&e->base.link, &e->base.file_priv->event_list);
+ wake_up_interruptible(&e->base.file_priv->event_wait);
+ trace_drm_vblank_event_delivered(e->base.pid, e->pipe,
+ e->event.sequence);
+ }
+
spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
}
EXPORT_SYMBOL(drm_vblank_off);