If the display is not enable()d, then we aren't holding a runtime PM
reference here. Thus, it's easy to accidentally cause a hang, if user
space is poking around at /dev/drm_dp_aux0 at the "wrong" time.
Let's get the panel and PM state right before trying to talk AUX.
Fixes: 0d97ad03f422 ("drm/bridge: analogix_dp: Remove duplicated code")
Cc: <stable@xxxxxxxxxxxxxxx>
Cc: Tomeu Vizoso <tomeu.vizoso@xxxxxxxxxxxxx>
Signed-off-by: Brian Norris <briannorris@xxxxxxxxxxxx>
---
Changes in v2:
- Fix spelling in Subject
- DRM_DEV_ERROR() -> drm_err()
- Propagate errors from un-analogix_dp_prepare_panel()
.../drm/bridge/analogix/analogix_dp_core.c | 21 ++++++++++++++++++-
1 file changed, 20 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
index b7d2e4449cfa..6fc46ac93ef8 100644
--- a/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
+++ b/drivers/gpu/drm/bridge/analogix/analogix_dp_core.c
@@ -1632,8 +1632,27 @@ static ssize_t analogix_dpaux_transfer(struct drm_dp_aux *aux,
struct drm_dp_aux_msg *msg)
{
struct analogix_dp_device *dp = to_dp(aux);
+ int ret, ret2;
- return analogix_dp_transfer(dp, msg);
+ ret = analogix_dp_prepare_panel(dp, true, false);
+ if (ret) {
+ drm_err(dp->drm_dev, "Failed to prepare panel (%d)\n", ret);
+ return ret;
+ }
+
+ pm_runtime_get_sync(dp->dev);
+ ret = analogix_dp_transfer(dp, msg);
+ pm_runtime_put(dp->dev);
+
+ ret2 = analogix_dp_prepare_panel(dp, false, false);
+ if (ret2) {
+ drm_err(dp->drm_dev, "Failed to unprepare panel (%d)\n", ret2);
+ /* Prefer the analogix_dp_transfer() error, if it exists. */
+ if (!ret)
+ ret = ret2;
+ }
+
+ return ret;
}
struct analogix_dp_device *
--
2.33.0.800.g4c38ced690-goog
