drm/i915: set vblank enabled flag correctly across IRQ install/uninstall
In the absence of kernel mode setting, many drivers disable IRQs across VT
switch. The core DRM vblank code is missing a check for this case however;
even after IRQ disable, the vblank code will still have the vblank_enabled
flag set, so unless we track the fact that they're disabled at IRQ uninstall
time, when we VT switch back in we won't actually re-enable them, which means
any apps waiting on vblank before the switch will hang.
This patch does that and also adds a sanity check to the wait condition to
look for the irq_enabled flag in general, as well as adding a wakeup to the
IRQ uninstall path.
Fixes fdo bug #18879 with compiz hangs at VT switch.
Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Dave Airlie <airlied@linux.ie>
diff --git a/drivers/gpu/drm/drm_irq.c b/drivers/gpu/drm/drm_irq.c
index 724e505..477caa1 100644
--- a/drivers/gpu/drm/drm_irq.c
+++ b/drivers/gpu/drm/drm_irq.c
@@ -267,7 +267,8 @@
*/
int drm_irq_uninstall(struct drm_device * dev)
{
- int irq_enabled;
+ unsigned long irqflags;
+ int irq_enabled, i;
if (!drm_core_check_feature(dev, DRIVER_HAVE_IRQ))
return -EINVAL;
@@ -277,6 +278,16 @@
dev->irq_enabled = 0;
mutex_unlock(&dev->struct_mutex);
+ /*
+ * Wake up any waiters so they don't hang.
+ */
+ spin_lock_irqsave(&dev->vbl_lock, irqflags);
+ for (i = 0; i < dev->num_crtcs; i++) {
+ DRM_WAKEUP(&dev->vbl_queue[i]);
+ dev->vblank_enabled[i] = 0;
+ }
+ spin_unlock_irqrestore(&dev->vbl_lock, irqflags);
+
if (!irq_enabled)
return -EINVAL;
@@ -652,8 +663,9 @@
vblwait->request.sequence, crtc);
dev->last_vblank_wait[crtc] = vblwait->request.sequence;
DRM_WAIT_ON(ret, dev->vbl_queue[crtc], 3 * DRM_HZ,
- ((drm_vblank_count(dev, crtc)
- - vblwait->request.sequence) <= (1 << 23)));
+ (((drm_vblank_count(dev, crtc) -
+ vblwait->request.sequence) <= (1 << 23)) ||
+ !dev->irq_enabled));
if (ret != -EINTR) {
struct timeval now;