[PATCH v2 5/5] drm/bridge: it6505: skip auto training when previous try fail

From: Hermes Wu via B4 Relay
Date: Wed Mar 26 2025 - 01:34:47 EST


From: Hermes Wu <Hermes.wu@xxxxxxxxxx>

When connect to device which can only training done by
step training, skip auto training when link training restart,
usually happen when display resolution is changed.

Signed-off-by: Hermes Wu <Hermes.wu@xxxxxxxxxx>
---
drivers/gpu/drm/bridge/ite-it6505.c | 29 +++++++++++++++++------------
1 file changed, 17 insertions(+), 12 deletions(-)

diff --git a/drivers/gpu/drm/bridge/ite-it6505.c b/drivers/gpu/drm/bridge/ite-it6505.c
index 2bbe787ccb1b57906f2a31a011dd92f327019b08..47f8134df8b6f5c2172c6cfdbc91da8063993a05 100644
--- a/drivers/gpu/drm/bridge/ite-it6505.c
+++ b/drivers/gpu/drm/bridge/ite-it6505.c
@@ -467,6 +467,7 @@ struct it6505 {
struct delayed_work hdcp_work;
struct work_struct hdcp_wait_ksv_list;
struct completion extcon_completion;
+ u8 step_train_only;
bool hdcp_desired;
bool is_repeater;
u8 hdcp_down_stream_count;
@@ -2457,11 +2458,13 @@ static void it6505_link_step_train_process(struct it6505 *it6505)
ret ? "pass" : "failed", i + 1);
if (ret) {
it6505_link_train_ok(it6505);
+ it6505->step_train_only = true;
return;
}
}

DRM_DEV_DEBUG_DRIVER(dev, "training fail");
+ it6505->step_train_only = false;
it6505->link_state = LINK_IDLE;
it6505_video_reset(it6505);
}
@@ -2477,18 +2480,19 @@ static void it6505_link_training_work(struct work_struct *work)

if (!it6505_get_sink_hpd_status(it6505))
return;
-
- for (retry = AUTO_TRAIN_RETRY; retry > 0; retry--) {
- it6505_link_training_setup(it6505);
- it6505_reset_hdcp(it6505);
- it6505_aux_reset(it6505);
-
- ret = it6505_link_start_auto_train(it6505);
- DRM_DEV_DEBUG_DRIVER(dev, "auto train %s,",
- ret ? "pass" : "failed");
- if (ret) {
- it6505_link_train_ok(it6505);
- return;
+ if (!it6505->step_train_only) {
+ for (retry = AUTO_TRAIN_RETRY; retry > 0; retry--) {
+ it6505_link_training_setup(it6505);
+ it6505_reset_hdcp(it6505);
+ it6505_aux_reset(it6505);
+
+ ret = it6505_link_start_auto_train(it6505);
+ DRM_DEV_DEBUG_DRIVER(dev, "auto train %s,",
+ ret ? "pass" : "failed");
+ if (ret) {
+ it6505_link_train_ok(it6505);
+ return;
+ }
}
}

@@ -2599,6 +2603,7 @@ static void it6505_irq_hpd(struct it6505 *it6505)
it6505_variable_config(it6505);
it6505_parse_link_capabilities(it6505);
}
+ it6505->step_train_only = false;

it6505_drm_dp_link_set_power(&it6505->aux, &it6505->link,
DP_SET_POWER_D0);

--
2.34.1