drm/i915: set vblank enabled flag correctly across IRQ install/uninstall (dc1336ff) · Commits · 戴 / test

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>

drivers/gpu/drm/drm_irq.c

+15 −3

Original line number	Diff line number	Diff line
		@@ -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;

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