On Mon, Mar 13, 2017 at 1:12 AM, Lee, Shawn C <shawn.c.lee@xxxxxxxxx> wrote: > From: "Lee, Shawn C" <shawn.c.lee@xxxxxxxxx> > > Display driver read DPCD register 0x202, 0x203 and 0x204 to identify > eDP sink status.If PSR exit is ongoing at eDP sink, and eDP source > read these registers at the same time. Panel will report EQ & symbol > lock not done. It will cause panel display flicking. > > Try to read link status more times if eDP EQ not done. Panel side > request at least 1000us for fast link train while doing PSR exit. > So wait more than 1000us then retrieve sink's status again. it is missing a v2 and v3 here with explanations on the changes. It was hard to follow the changes. > > Bugzilla: https://bugs.freedesktop.org/show_bug.cgi?id=99639 > TEST=Reboot DUT and no flicking on local display at login screen > > Cc: Cooper Chiou <cooper.chiou@xxxxxxxxx> > Cc: Wei Shun Chen <wei.shun.chang@xxxxxxxxx> > Cc: Gary C Wang <gary.c.wang@xxxxxxxxx> > Cc: Jani Nikula <jani.nikula@xxxxxxxxx> > Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx> > > Signed-off-by: Lee, Shawn C <shawn.c.lee@xxxxxxxxx> > --- > drivers/gpu/drm/i915/intel_dp.c | 34 ++++++++++++++++++++++++---------- > 1 file changed, 24 insertions(+), 10 deletions(-) > > diff --git a/drivers/gpu/drm/i915/intel_dp.c b/drivers/gpu/drm/i915/intel_dp.c > index 024798a9c016..d50827a92aa2 100644 > --- a/drivers/gpu/drm/i915/intel_dp.c > +++ b/drivers/gpu/drm/i915/intel_dp.c > @@ -4225,15 +4225,11 @@ static void intel_dp_handle_test_request(struct intel_dp *intel_dp) > { > struct intel_encoder *intel_encoder = &dp_to_dig_port(intel_dp)->base; > struct drm_device *dev = intel_dp_to_dev(intel_dp); > - u8 link_status[DP_LINK_STATUS_SIZE]; > + struct drm_i915_private *dev_priv = dev->dev_private; > + u8 link_status[DP_LINK_STATUS_SIZE], retry = 1; > > WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex)); > > - if (!intel_dp_get_link_status(intel_dp, link_status)) { > - DRM_ERROR("Failed to get link status\n"); > - return; > - } > - > if (!intel_encoder->base.crtc) > return; > > @@ -4245,13 +4241,31 @@ static void intel_dp_handle_test_request(struct intel_dp *intel_dp) > if (!intel_dp->lane_count) > return; > > + if (is_edp(intel_dp) && dev_priv->psr.enabled) > + retry = 3; > + > /* Retrain if Channel EQ or CR not ok */ > - if (!drm_dp_channel_eq_ok(link_status, intel_dp->lane_count)) { > - DRM_DEBUG_KMS("%s: channel EQ not ok, retraining\n", > - intel_encoder->base.name); > + while ( retry-- ) { > + if (!intel_dp_get_link_status(intel_dp, link_status)) { > + DRM_ERROR("Failed to get link status\n"); > + return; Well, if link status is not ok you return without retrying, so, why is this here? > + } > > - intel_dp_retrain_link(intel_dp); > + if (drm_dp_channel_eq_ok(link_status, intel_dp->lane_count)) > + return; > + > + /* > + * EQ not ok may caused by fast link train while exit PSR active, > + * wait at least 1000 us then read it again. > + */ > + if (retry) > + usleep_range(1000, 1500); maybe this retry is randomly just masking the real issue. Jim recently found out that on psr enable we are clearing a bit that we should never touch by spec. I'd try Jim's patch(es) first to see if they solve the issue for you. > } > + > + DRM_DEBUG_KMS("%s: channel EQ not ok, retraining\n", > + intel_encoder->base.name); > + > + intel_dp_retrain_link(intel_dp); > } > > /* > -- > 1.7.9.5 > > _______________________________________________ > Intel-gfx mailing list > Intel-gfx@xxxxxxxxxxxxxxxxxxxxx > https://lists.freedesktop.org/mailman/listinfo/intel-gfx -- Rodrigo Vivi Blog: http://blog.vivi.eng.br _______________________________________________ Intel-gfx mailing list Intel-gfx@xxxxxxxxxxxxxxxxxxxxx https://lists.freedesktop.org/mailman/listinfo/intel-gfx
