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@xxxxxxxxxxxxx>
---
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;
--
2.25.1
