[Intel-gfx] [PATCH] drm/i915: take mode config lock around crtc disable at suspend

[Jesse Barnes]

This is just a theoretical issue, but we need to do this to prevent the
WARN in pipe_from_connector at suspend time.

https://bugs.freedesktop.org/show_bug.cgi?id=71978
Signed-off-by: Jesse Barnes <jbarnes at virtuousgeek.org>
---
 drivers/gpu/drm/i915/i915_drv.c |    2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/gpu/drm/i915/i915_drv.c b/drivers/gpu/drm/i915/i915_drv.c
index 13076db..0ec0fb3 100644
--- a/drivers/gpu/drm/i915/i915_drv.c
+++ b/drivers/gpu/drm/i915/i915_drv.c
@@ -535,8 +535,10 @@ static int i915_drm_freeze(struct drm_device *dev)
 		 * Disable CRTCs directly since we want to preserve sw state
 		 * for _thaw.
 		 */
+		mutex_lock(&dev->mode_config.mutex);
 		list_for_each_entry(crtc, &dev->mode_config.crtc_list, head)
 			dev_priv->display.crtc_disable(crtc);
+		mutex_unlock(&dev->mode_config.mutex);
 
 		intel_modeset_suspend_hw(dev);
 	}
-- 
1.7.9.5