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drm/bridge: Fixed a DP link training bug

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[ 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@ite.corp-partner.google.com>
Signed-off-by: xiazhengqiao <xiazhengqiao@huaqin.corp-partner.google.com>
Reviewed-by: Robert Foss <rfoss@kernel.org>
Signed-off-by: Robert Foss <rfoss@kernel.org>
Link: https://patchwork.freedesktop.org/patch/msgid/20231221093057.7073-1-xiazhengqiao@huaqin.corp-partner.google.com
Stable-dep-of: 484436ec5c2b ("drm/bridge: it6505: fix hibernate to resume no display issue")
Signed-off-by: Sasha Levin <sashal@kernel.org>
This commit is contained in:
xiazhengqiao
2023-12-21 17:30:57 +08:00
committed by Greg Kroah-Hartman
parent c9bec33bd4
commit 2918b50ad6
1 changed files with 3 additions and 1 deletions
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4
drivers/gpu/drm/bridge/ite-it6505.c
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@@ -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);