On Wed, 27 Apr 2011 16:10:57 +1000 christopher.halse.rogers@canonical.com wrote:
From: Christopher James Halse Rogers christopher.halse.rogers@canonical.com
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
drivers/gpu/drm/drm_irq.c | 23 +++++++++++++++++++++++ 1 files changed, 23 insertions(+), 0 deletions(-)
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c index 741457b..a1f12cb 100644 --- a/drivers/gpu/drm/drm_irq.c +++ b/drivers/gpu/drm/drm_irq.c @@ -932,11 +932,34 @@ 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);
Yeah, this matches what we do for the blocking waits, and it's probably a good idea. Userspace can decide what to do with apps running against a disabled CRTC.
Would be nice to share the code with drm_handle_vblank_events though somehow. Looks like
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);
could be pulled out into a separate function for both to use.