Commit 0a6759c6 authored Jul 04, 2012 by Daniel Vetter

drm/i915: don't hang userspace when the gpu reset is stuck



With the gpu reset no longer using a trylock we've increased the
chances of userspace getting stuck quite a bit. To make that
(hopefully) rare case more paletable time out when waiting for the gpu
reset code to complete and signal this little issue to the caller by
returning -EIO.

This should help userspace to somewhat gracefully fall back and
hopefully allow the user to grab some logs and reboot the machine
(instead of staring at a frozen X screen in agony).

Suggested by Chris Wilson because I've been stubborn about allowing
the gpu reset code no to fail, ever (by removing the trylock).

Reviewed-by: Chris Wilson <chris@chris-wilson.co.uk>
Tested-by: Chris Wilson <chris@chris-wilson.co.uk>
Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

parent d6b2c790

drivers/gpu/drm/i915/i915_gem.c

+11 −2

Original line number	Diff line number	Diff line
		@@ -96,9 +96,18 @@ i915_gem_wait_for_error(struct drm_device *dev)
		if (!atomic_read(&dev_priv->mm.wedged))
		return 0;

		ret = wait_for_completion_interruptible(x);
		if (ret)
		/*
		* Only wait 10 seconds for the gpu reset to complete to avoid hanging
		* userspace. If it takes that long something really bad is going on and
		* we should simply try to bail out and fail as gracefully as possible.
		*/
		ret = wait_for_completion_interruptible_timeout(x, 10*HZ);
		if (ret == 0) {
		DRM_ERROR("Timed out waiting for the gpu reset to complete\n");
		return -EIO;
		} else if (ret < 0) {
		return ret;
		}

		if (atomic_read(&dev_priv->mm.wedged)) {
		/* GPU is hung, bump the completion count to account for