[PATCH 4/5] drm/i915: properly SIGBUS on I/O errors

[Daniel Vetter <daniel.vetter@ffwll.ch>]

... instead of looping endless with no hope of ever serving that
page-fault. We only need to break out of this loop when the gpu died,
to run the reset work (and hopefully resurrect it).

This seems to have been lost in:

commit d9bc7e9f32716901c617e1f0fb6ce0f74f172686
Author: Chris Wilson <chris@chris-wilson.co.uk>
Date:   Mon Feb 7 13:09:31 2011 +0000

    drm/i915: Fix infinite loop regression from 21dd3734

Signed-Off-by: Daniel Vetter <daniel.vetter@ffwll.ch>
---
 drivers/gpu/drm/i915/i915_gem.c |    5 +++++
 1 file changed, 5 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_gem.c b/drivers/gpu/drm/i915/i915_gem.c
index 7d28555..2b54142 100644
--- a/drivers/gpu/drm/i915/i915_gem.c
+++ b/drivers/gpu/drm/i915/i915_gem.c
@@ -1141,6 +1141,11 @@ unlock:
 out:
 	switch (ret) {
 	case -EIO:
+		/* If this -EIO is due to a gpu hang, give the reset code a
+		 * chance to clean up the mess. Otherwise return the proper
+		 * SIGBUS. */
+		if (!atomic_read(&dev_priv->mm.wedged))
+			return VM_FAULT_SIGBUS;
 	case -EAGAIN:
 		/* Give the error handler a chance to run and move the
 		 * objects off the GPU active list. Next time we service the
-- 
1.7.10