Depending on the bridge code, certain userspace events during a driver teardown (such as a DRM ioctl call) might cause a race condition where the drm_bridge_chain_pre_enable() and drm_bridge_chain_post_enable() functions could be called for a bridge that has just been detached and removed from the bridge chain of an encoder.
This change makes these functions a bit more robust by bailing out if the bridge has already been detached.
Tested on an Acer Chromebook R13 (Elm, MT8173) with Debian Sid.
Signed-off-by: Ricardo Cañuelo ricardo.canuelo@collabora.com --- drivers/gpu/drm/drm_bridge.c | 4 ++-- 1 file changed, 2 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/drm_bridge.c b/drivers/gpu/drm/drm_bridge.c index c96847fc0ebc..e074aa456dd1 100644 --- a/drivers/gpu/drm/drm_bridge.c +++ b/drivers/gpu/drm/drm_bridge.c @@ -529,7 +529,7 @@ void drm_bridge_chain_post_disable(struct drm_bridge *bridge) { struct drm_encoder *encoder;
- if (!bridge) + if (!bridge || !bridge->dev) return;
encoder = bridge->encoder; @@ -585,7 +585,7 @@ void drm_bridge_chain_pre_enable(struct drm_bridge *bridge) struct drm_encoder *encoder; struct drm_bridge *iter;
- if (!bridge) + if (!bridge || !bridge->dev) return;
encoder = bridge->encoder;