2.6.28-stable review patch. If anyone has any objections, please let us know. ------------------ From: Jesse Barnes commit dc1336ff4fe08ae7cfe8301bfd7f0b2cfd31d20a upstream. 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 Signed-off-by: Eric Anholt Signed-off-by: Dave Airlie Signed-off-by: Greg Kroah-Hartman --- drivers/gpu/drm/drm_irq.c | 18 +++++++++++++++--- 1 file changed, 15 insertions(+), 3 deletions(-) --- a/drivers/gpu/drm/drm_irq.c +++ b/drivers/gpu/drm/drm_irq.c @@ -259,7 +259,8 @@ 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; @@ -269,6 +270,16 @@ int drm_irq_uninstall(struct drm_device 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; @@ -617,8 +628,9 @@ int drm_wait_vblank(struct drm_device *d DRM_DEBUG("waiting on vblank count %d, crtc %d\n", vblwait->request.sequence, crtc); 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; -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/