drm/i915: Be paranoid and bail on resetting if we can't take the lock.

This will declare the machine wedged, but is better than truly wedging
the machine.

Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 1a15b78..64844e2 100644 (file)
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -440,7 +440,8 @@ int i915_reset(struct drm_device *dev, u8 flags)
        bool need_display = true;
        int ret;
 
-       mutex_lock(&dev->struct_mutex);
+       if (!mutex_trylock(&dev->struct_mutex))
+               return -EBUSY;
 
        i915_gem_reset(dev);