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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>
This commit is contained in:
Jesse Barnes 2009-01-06 10:21:24 -08:00 committed by Dave Airlie
parent 71e0ffa599
commit dc1336ff4f
1 changed files with 15 additions and 3 deletions
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18
drivers/gpu/drm/drm_irq.c
View File

@ -267,7 +267,8 @@ EXPORT_SYMBOL(drm_irq_install);
*/
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 @@ int drm_irq_uninstall(struct drm_device * dev)
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 @@ int drm_wait_vblank(struct drm_device *dev, void *data,
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;