Per fdo bz #18041, we timeout if a vblank event doesn't occur within a
specified time period. However, this wait happens in libdrm, so old
userspace can still end up hanging, waiting for a vblank event that may never
occur. So add a more reasonable timeout value to drm_wait_vblank and make
the wait uninterruptible, so that the X server's scheduling signals don't get
in the way.
Reported-by: Linus Torvalds <torva...@linux-foundation.org>
Tested-by: Linus Torvalds <torva...@linux-foundation.org>
Signed-off-by: Jesse Barnes <jbar...@virtuousgeek.org>
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
index 69aa0ab..c5df063 100644
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -539,9 +539,11 @@ out:
int drm_wait_vblank(struct drm_device *dev, void *data,
struct drm_file *file_priv)
{
+ struct timeval now;
union drm_wait_vblank *vblwait = data;
int ret = 0;
unsigned int flags, seq, crtc;
+ int timeout, max_wait = (DRM_HZ / 40) * 100; /* 100ms max */
if ((!dev->pdev->irq) || (!dev->irq_enabled))
return -EINVAL;
@@ -588,25 +590,24 @@ int drm_wait_vblank(struct drm_device *dev, void *data,
DRM_DEBUG("waiting on vblank count %d, crtc %d\n",
vblwait->request.sequence, crtc);
+
+ /* Wait at most 25ms * number of frames */
+ timeout = (DRM_HZ / 40) * (vblwait->request.sequence - seq);
+ if (timeout > max_wait)
+ timeout = max_wait;
+
dev->last_vblank_wait[crtc] = vblwait->request.sequence;
- DRM_WAIT_ON(ret, dev->vbl_queue[crtc], 3 * DRM_HZ,
+ DRM_WAIT_ON_UNINTERRUPTIBLE(ret, dev->vbl_queue[crtc], timeout,
(((drm_vblank_count(dev, crtc) -
vblwait->request.sequence) <= (1 << 23)) ||
!dev->irq_enabled));
- if (ret != -EINTR) {
- struct timeval now;
+ do_gettimeofday(&now);
- do_gettimeofday(&now);
-
- vblwait->reply.tval_sec = now.tv_sec;
- vblwait->reply.tval_usec = now.tv_usec;
- vblwait->reply.sequence = drm_vblank_count(dev, crtc);
- DRM_DEBUG("returning %d to client\n",
- vblwait->reply.sequence);
- } else {
- DRM_DEBUG("vblank wait interrupted by signal\n");
- }
+ vblwait->reply.tval_sec = now.tv_sec;
+ vblwait->reply.tval_usec = now.tv_usec;
+ vblwait->reply.sequence = drm_vblank_count(dev, crtc);
+ DRM_DEBUG("returning %d to client\n", vblwait->reply.sequence);
done:
drm_vblank_put(dev, crtc);
diff --git a/include/drm/drm_os_linux.h b/include/drm/drm_os_linux.h
index 8dbd257..67afee8 100644
--- a/include/drm/drm_os_linux.h
+++ b/include/drm/drm_os_linux.h
@@ -104,5 +104,25 @@ do {
\
remove_wait_queue(&(queue), &entry); \
} while (0)
+#define DRM_WAIT_ON_UNINTERRUPTIBLE( ret, queue, timeout, condition ) \
+do { \
+ DECLARE_WAITQUEUE(entry, current); \
+ unsigned long end = jiffies + (timeout); \
+ add_wait_queue(&(queue), &entry); \
+ \
+ for (;;) { \
+ __set_current_state(TASK_UNINTERRUPTIBLE); \
+ if (condition) \
+ break; \
+ if (time_after_eq(jiffies, end)) { \
+ ret = -EBUSY; \
+ break; \
+ } \
+ schedule_timeout((HZ/100 > 1) ? HZ/100 : 1); \
+ } \
+ __set_current_state(TASK_RUNNING); \
+ remove_wait_queue(&(queue), &entry); \
+} while (0)
+
#define DRM_WAKEUP( queue ) wake_up_interruptible( queue )
#define DRM_INIT_WAITQUEUE( queue ) init_waitqueue_head( queue )
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