On Fri, Aug 20, 2021 at 08:26:14PM +0300, Ville Syrjälä wrote:
On Fri, Aug 20, 2021 at 03:52:59PM +0800, Kai-Heng Feng wrote:
Users reported that after commit 2bbd6dba84d4 ("drm/i915: Try to use fast+narrow link on eDP again and fall back to the old max strategy on failure"), the screen starts to have wobbly effect.
Commit a5c936add6a2 ("drm/i915/dp: Use slow and wide link training for everything") doesn't help either, that means the affected eDP 1.2 panels only work with max params.
So use max params for panels < eDP 1.4 as Windows does to solve the issue.
v3:
- Do the eDP rev check in intel_edp_init_dpcd()
v2:
- Check eDP 1.4 instead of DPCD 1.1 to apply max params
Closes: https://gitlab.freedesktop.org/drm/intel/-/issues/3714 Fixes: 2bbd6dba84d4 ("drm/i915: Try to use fast+narrow link on eDP again and fall back to the old max strategy on failure") Fixes: a5c936add6a2 ("drm/i915/dp: Use slow and wide link training for everything") Suggested-by: Ville Syrjälä ville.syrjala@linux.intel.com Signed-off-by: Kai-Heng Feng kai.heng.feng@canonical.com
Slapped a cc:stable on it and pushed to drm-intel-next. Thanks.
Since I got a strange failure on CI_DIF_604 that I don't see on CI_DIF_603, I'm avoiding the display patches. This one and also dab1b47e57e0 ("drm/i915/dp: return proper DPRX link training result")
I know, it is probably the other one, but I had to remove both patches for now and I'm not confident the CI will allow me to test with this one alone.
If we have -rc8 I will check again later. Otherwise we will have to send to the stable mailing list later.
drivers/gpu/drm/i915/display/intel_dp.c | 5 ++++- 1 file changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/i915/display/intel_dp.c b/drivers/gpu/drm/i915/display/intel_dp.c index 75d4ebc669411..e0dbd35ae7bc0 100644 --- a/drivers/gpu/drm/i915/display/intel_dp.c +++ b/drivers/gpu/drm/i915/display/intel_dp.c @@ -2445,11 +2445,14 @@ intel_edp_init_dpcd(struct intel_dp *intel_dp) */ if (drm_dp_dpcd_read(&intel_dp->aux, DP_EDP_DPCD_REV, intel_dp->edp_dpcd, sizeof(intel_dp->edp_dpcd)) ==
sizeof(intel_dp->edp_dpcd))
sizeof(intel_dp->edp_dpcd)) {drm_dbg_kms(&dev_priv->drm, "eDP DPCD: %*ph\n", (int)sizeof(intel_dp->edp_dpcd), intel_dp->edp_dpcd);
intel_dp->use_max_params = intel_dp->edp_dpcd[0] < DP_EDP_14;}
/*
- This has to be called after intel_dp->edp_dpcd is filled, PSR checks
- for SET_POWER_CAPABLE bit in intel_dp->edp_dpcd[1]
-- 2.32.0
-- Ville Syrjälä Intel