[PATCH 6.1 034/131] drm/msm/dp: do not reinitialize phy unless retry during link training

Greg Kroah-Hartman
2023-10-16T08:54:25Z

From: Kuogee Hsieh <quic_khsieh@quicinc.com>

[ Upstream commit 0c1a2e69bcb506f48ebf94bd199bab0b93f66da2 ]

DP PHY re-initialization done using dp_ctrl_reinitialize_mainlink() will
cause PLL unlocked initially and then PLL gets locked at the end of
initialization. PLL_UNLOCKED interrupt will fire during this time if the
interrupt mask is enabled.

However currently DP driver link training implementation incorrectly
re-initializes PHY unconditionally during link training as the PHY was
already configured in dp_ctrl_enable_mainlink_clocks().

Fix this by re-initializing the PHY only if the previous link training
failed.

[drm:dp_aux_isr] *ERROR* Unexpected DP AUX IRQ 0x01000000 when not busy

Fixes: c943b4948b58 ("drm/msm/dp: add displayPort driver support")
Closes: https://gitlab.freedesktop.org/drm/msm/-/issues/30
Signed-off-by: Kuogee Hsieh <quic_khsieh@quicinc.com>
Tested-by: Abhinav Kumar <quic_abhinavk@quicinc.com> # sc7280
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Reviewed-by: Stephen Boyd <swboyd@chromium.org>
Reviewed-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Tested-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Patchwork: https://patchwork.freedesktop.org/patch/551847/
Link: https://lore.kernel.org/r/1691533190-19335-1-git-send-email-quic_khsieh@quicinc.com
[quic_abhinavk@quicinc.com: added line break in commit text]
Signed-off-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
drivers/gpu/drm/msm/dp/dp_ctrl.c | 13 ++++++-------
1 file changed, 6 insertions(+), 7 deletions(-)

diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c
index dd26ca651a054..103eef9f059a0 100644
--- a/drivers/gpu/drm/msm/dp/dp_ctrl.c
+++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c
@@ -1711,13 +1711,6 @@ int dp_ctrl_on_link(struct dp_ctrl *dp_ctrl)
return rc;

while (--link_train_max_retries) {
- rc = dp_ctrl_reinitialize_mainlink(ctrl);
- if (rc) {
- DRM_ERROR("Failed to reinitialize mainlink. rc=%d\n",
- rc);
- break;
- }
-
training_step = DP_TRAINING_NONE;
rc = dp_ctrl_setup_main_link(ctrl, &training_step);
if (rc == 0) {
@@ -1769,6 +1762,12 @@ int dp_ctrl_on_link(struct dp_ctrl *dp_ctrl)
/* stop link training before start re training */
dp_ctrl_clear_training_pattern(ctrl);
}
+
+ rc = dp_ctrl_reinitialize_mainlink(ctrl);
+ if (rc) {
+ DRM_ERROR("Failed to reinitialize mainlink. rc=%d\n", rc);
+ break;
+ }
}

if (ctrl->link->sink_request & DP_TEST_LINK_PHY_TEST_PATTERN)
--
2.40.1