This is a note to let you know that I've just added the patch titled
drm/bridge: Fixed a DP link training bug
to the 6.6-stable tree which can be found at:
http://www.kernel.org/git/?p=linux/kernel/git/stable/stable-queue.git;a=summary
The filename of the patch is:
drm-bridge-fixed-a-dp-link-training-bug.patch
and it can be found in the queue-6.6 subdirectory.
If you, or anyone else, feels it should not be added to the stable tree,
please let <stable@xxxxxxxxxxxxxxx> know about it.
commit 4b754950e249efcefeba6f08a9479752bd27bcdf
Author: xiazhengqiao <xiazhengqiao@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
Date: Thu Dec 21 17:30:57 2023 +0800
drm/bridge: Fixed a DP link training bug
[ Upstream commit ca077ff8cac5af8a5a3c476983a6dd54aa3511b7 ]
To have better compatibility for DP sink, there is a retry mechanism
for the link training process to switch between different training process.
The original driver code doesn't reset the retry counter when training
state is pass. If the system triggers link training over 3 times,
there will be a chance to causes the driver to use the wrong training
method and return a training fail result.
To Fix this, we reset the retry counter when training state is pass
each time.
Signed-off-by: Allen Chen <allen.chen@xxxxxxxxxxxxxxxxxxxxxxxxxxx>
Signed-off-by: xiazhengqiao <xiazhengqiao@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx>
Reviewed-by: Robert Foss <rfoss@xxxxxxxxxx>
Signed-off-by: Robert Foss <rfoss@xxxxxxxxxx>
Link: https://patchwork.freedesktop.org/patch/msgid/20231221093057.7073-1-xiazhengqiao@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Stable-dep-of: 484436ec5c2b ("drm/bridge: it6505: fix hibernate to resume no display issue")
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
diff --git a/drivers/gpu/drm/bridge/ite-it6505.c b/drivers/gpu/drm/bridge/ite-it6505.c
index 2f300f5ca051c..b589136ca6da9 100644
--- a/drivers/gpu/drm/bridge/ite-it6505.c
+++ b/drivers/gpu/drm/bridge/ite-it6505.c
@@ -2240,11 +2240,13 @@ static void it6505_link_training_work(struct work_struct *work)
ret = it6505_link_start_auto_train(it6505);
DRM_DEV_DEBUG_DRIVER(dev, "auto train %s, auto_train_retry: %d",
ret ? "pass" : "failed", it6505->auto_train_retry);
- it6505->auto_train_retry--;
if (ret) {
+ it6505->auto_train_retry = AUTO_TRAIN_RETRY;
it6505_link_train_ok(it6505);
return;
+ } else {
+ it6505->auto_train_retry--;
}
it6505_dump(it6505);
