drm/i915: Deal with video overlay on GPU reset

Clear the video overlay state on GPU reset. Any pending overlay request
in the ring has been nuked, and the display itself gets reset. So we
pretty much lose all state here. Adjust the software state to match so
that the next "putimage" will restore things to working order.

v2: Ass a locking check into intel_overlay_release_old_vid() (Daniel)

Cc: Daniel Vetter <daniel@ffwll.ch>
Signed-off-by: NVille Syrjälä <ville.syrjala@linux.intel.com>
[danvet: s/0/NULL/ to appease sparse, reported by 0-day tester.]
Signed-off-by: NDaniel Vetter <daniel.vetter@ffwll.ch>

drivers/gpu/drm/i915/i915_drv.c

@@ -838,6 +838,8 @@ int i915_reset(struct drm_device *dev)
 		return ret;
 	}
 
+	intel_overlay_reset(dev_priv);
+
 	/* Ok, now get things going again... */
 
 	/*

drivers/gpu/drm/i915/intel_drv.h

@@ -1081,6 +1081,7 @@ int intel_overlay_put_image(struct drm_device *dev, void *data,
 			    struct drm_file *file_priv);
 int intel_overlay_attrs(struct drm_device *dev, void *data,
 			struct drm_file *file_priv);
+void intel_overlay_reset(struct drm_i915_private *dev_priv);
 
 
 /* intel_panel.c */

drivers/gpu/drm/i915/intel_overlay.c

@@ -394,6 +394,8 @@ static int intel_overlay_release_old_vid(struct intel_overlay *overlay)
 	struct intel_engine_cs *ring = &dev_priv->ring[RCS];
 	int ret;
 
+	WARN_ON(!mutex_is_locked(&dev->struct_mutex));
+
 	/* Only wait if there is actually an old frame to release to
 	 * guarantee forward progress.
 	 */
@@ -424,6 +426,22 @@ static int intel_overlay_release_old_vid(struct intel_overlay *overlay)
 	return 0;
 }
 
+void intel_overlay_reset(struct drm_i915_private *dev_priv)
+{
+	struct intel_overlay *overlay = dev_priv->overlay;
+
+	if (!overlay)
+		return;
+
+	intel_overlay_release_old_vid(overlay);
+
+	overlay->last_flip_req = NULL;
+	overlay->old_xscale = 0;
+	overlay->old_yscale = 0;
+	overlay->crtc = NULL;
+	overlay->active = false;
+}
+
 struct put_image_params {
 	int format;
 	short dst_x;