Messages in this thread | | | Date | Mon, 1 Aug 2022 13:08:13 -0700 | Subject | Re: [PATCH] drm/msm/dp: delete DP_RECOVERED_CLOCK_OUT_EN to fix tps4 | From | Kuogee Hsieh <> |
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On 8/1/2022 12:51 PM, Stephen Boyd wrote: > Quoting Kuogee Hsieh (2022-08-01 12:42:50) >> 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. >> >> Fixes: 956653250b21 ("drm/msm/dp: add support of tps4 (training pattern 4) for HBR3") >> >> Signed-off-by: Kuogee Hsieh <quic_khsieh@quicinc.com> >> --- >> 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 ab6aa13..013ca02 100644 >> --- a/drivers/gpu/drm/msm/dp/dp_ctrl.c >> +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c >> @@ -1214,7 +1214,7 @@ 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); > This line is from the first patch introducing this driver. Even if this > is fixing tps4 support, it sounds like the bit should never have been > enabled in the first place. Why isn't the fixes tag targeted at the > first commit? Does it hurt to apply it without commit 956653250b21? agree, it should be fixed to first patch
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