drm/i915: Mark device as wedged if we fail to resume

During module load, if we fail to initialise the rings, we abort the
load reporting EIO. However during resume, even though we report EIO as
we fail to reinitialize the ringbuffers, the resume continues and the
device is restored - albeit in a non-functional state. As we cannot
execute any commands on the GPU, it is effectively wedged, mark it so.

As we now preserve the ringbuffers across resume, this should prevent
UXA from falling into the trap of repeatedly sending invalid
batchbuffers and dropping all further rendering into /dev/null.

Reported-and-tested-by: Jiri Kosina <jkosina@suse.cz>
References: https://bugs.freedesktop.org/show_bug.cgi?id=76554
Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
Reviewed-by: Oscar Mateo <oscar.mateo@intel.com>
[danvet: Drop unused error, spotted by Oscar.]
Signed-off-by: Daniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.c

@@ -551,7 +551,6 @@ static int i915_drm_thaw_early(struct drm_device *dev)
 static int __i915_drm_thaw(struct drm_device *dev, bool restore_gtt_mappings)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
-	int error = 0;
 
 	if (drm_core_check_feature(dev, DRIVER_MODESET) &&
 	    restore_gtt_mappings) {
@@ -569,8 +568,10 @@ static int __i915_drm_thaw(struct drm_device *dev, bool restore_gtt_mappings)
 		drm_mode_config_reset(dev);
 
 		mutex_lock(&dev->struct_mutex);
-
-		error = i915_gem_init_hw(dev);
+		if (i915_gem_init_hw(dev)) {
+			DRM_ERROR("failed to re-initialize GPU, declaring wedged!\n");
+			atomic_set_mask(I915_WEDGED, &dev_priv->gpu_error.reset_counter);
+		}
 		mutex_unlock(&dev->struct_mutex);
 
 		/* We need working interrupts for modeset enabling ... */
@@ -613,7 +614,7 @@ static int __i915_drm_thaw(struct drm_device *dev, bool restore_gtt_mappings)
 	mutex_unlock(&dev_priv->modeset_restore_lock);
 
 	intel_runtime_pm_put(dev_priv);
-	return error;
+	return 0;
 }
 
 static int i915_drm_thaw(struct drm_device *dev)