diff mbox series

[RESEND] drm/bridge: Fixed a DP link training bug

Message ID 20231221093057.7073-1-xiazhengqiao@huaqin.corp-partner.google.com (mailing list archive)
State New, archived
Headers show
Series [RESEND] drm/bridge: Fixed a DP link training bug | expand

Commit Message

Zhengqiao Xia Dec. 21, 2023, 9:30 a.m. UTC 
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@ite.corp-partner.google.com>
Signed-off-by: xiazhengqiao <xiazhengqiao@huaqin.corp-partner.google.com>
---
 drivers/gpu/drm/bridge/ite-it6505.c | 4 +++-
 1 file changed, 3 insertions(+), 1 deletion(-)

Comments

Robert Foss Jan. 9, 2024, 5:17 p.m. UTC | #1 
On Thu, 21 Dec 2023 17:30:57 +0800, xiazhengqiao wrote:
> 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.
> 
> [...]

Applied, thanks!

[1/1] drm/bridge: Fixed a DP link training bug
      https://cgit.freedesktop.org/drm/drm-misc/commit/?id=ca077ff8cac5



Rob
diff mbox series

Patch

diff --git a/drivers/gpu/drm/bridge/ite-it6505.c b/drivers/gpu/drm/bridge/ite-it6505.c
index 2f300f5ca051..b589136ca6da 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);