Commit dc1336ff authored by Jesse Barnes's avatar Jesse Barnes Committed by Dave Airlie
Browse files

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: default avatarJesse Barnes <>
Signed-off-by: default avatarEric Anholt <>
Signed-off-by: default avatarDave Airlie <>
parent 71e0ffa5
......@@ -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;
* Wake up any waiters so they don't hang.
spin_lock_irqsave(&dev->vbl_lock, irqflags);
for (i = 0; i < dev->num_crtcs; 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)) ||
if (ret != -EINTR) {
struct timeval now;
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