From: Kuogee Hsieh quic_khsieh@quicinc.com
[ Upstream commit 032d57960176ac01cc5adff5bcc5eb51317f8781 ]
Data Symbols scrambled is required for tps4 at link training 2. Therefore SCRAMBLING_DISABLE bit should not be set for tps4 to work.
RECOVERED_CLOCK_OUT_EN is for enable simple EYE test for jitter measurement with minimal equipment for embedded applications purpose and is not required to be set during normal operation. Current implementation always have RECOVERED_CLOCK_OUT_EN bit set which cause SCRAMBLING_DISABLE bit wrongly set at tps4 which prevent tps4 from working.
This patch delete setting RECOVERED_CLOCK_OUT_EN to fix SCRAMBLING_DISABLE be wrongly set at tps4.
Changes in v2: -- fix Fixes tag
Changes in v3: -- revise commit text
Changes in v4: -- fix commit text newline
Changes in v5: -- fix commit text line over 75 chars
Fixes: c943b4948b58 ("drm/msm/dp: add displayPort driver support") Signed-off-by: Kuogee Hsieh quic_khsieh@quicinc.com
Reviewed-by: Abhinav Kumar quic_abhinavk@quicinc.com Reviewed-by: Stephen Boyd swboyd@chromium.org Reviewed-by: Dmitry Baryshkov dmitry.baryshkov@linaro.org Patchwork: https://patchwork.freedesktop.org/patch/497194/ Link: https://lore.kernel.org/r/1660258670-4200-1-git-send-email-quic_khsieh@quici... 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 | 2 +- 1 file changed, 1 insertion(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c index b9ca844ce2ad0..9fac55c24214a 100644 --- a/drivers/gpu/drm/msm/dp/dp_ctrl.c +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c @@ -1205,7 +1205,7 @@ static int dp_ctrl_link_train_2(struct dp_ctrl_private *ctrl, if (ret) return ret;
- dp_ctrl_train_pattern_set(ctrl, pattern | DP_RECOVERED_CLOCK_OUT_EN); + dp_ctrl_train_pattern_set(ctrl, pattern);
for (tries = 0; tries <= maximum_retries; tries++) { drm_dp_link_train_channel_eq_delay(ctrl->panel->dpcd);