On Fri, Apr 28, 2017 at 03:08:53AM +0000, Lee, Shawn C wrote: > > > -----Original Message----- > From: Ville Syrjälä [mailto:ville.syrj...@linux.intel.com] > Sent: Thursday, April 27, 2017 10:39 PM > To: Lee, Shawn C <shawn.c....@intel.com> > Cc: intel-gfx@lists.freedesktop.org; Chiou, Cooper <cooper.ch...@intel.com>; > Bride, Jim <jim.br...@intel.com>; Nikula, Jani <jani.nik...@intel.com>; Vivi, > Rodrigo <rodrigo.v...@intel.com>; Lin, Ryan <ryan....@intel.com> > Subject: Re: [Intel-gfx] [PATCH] drm/i915/edp: Read link status after exit PSR > > On Thu, Apr 27, 2017 at 10:35:22PM +0800, Lee, Shawn C wrote: > > From: "Lee, Shawn C" <shawn.c....@intel.com> > > > > 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. > > So driver have to make sure PSR already exit before read link status. > > And what exactly guarantees that it will exit PSR eventually? > > When read DPCD link status register, eDP can't at link train stage (after PSR > exit).
There seem to be some important word(s) missing from that sentence. As is I don't really know what you're trying to say here. > TCON report EQ not done then will cause link re-training and display flicker. > So we read SRD_STATUS to make sure source did not send TP1, TP2, TP3 or idle > pattern to sink side for link training. That doesn't answer my question. > > > > > 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.ch...@intel.com> > > Cc: Jani Nikula <jani.nik...@intel.com> > > Cc: Rodrigo Vivi <rodrigo.v...@intel.com> > > Cc: Jim Bride <jim.br...@intel.com> > > Cc: Ryan Lin <ryan....@intel.com> > > > > Signed-off-by: Shawn Lee <shawn.c....@intel.com> > > --- > > drivers/gpu/drm/i915/intel_dp.c | 34 +++++++++++++++++++++++++++++----- > > 1 file changed, 29 insertions(+), 5 deletions(-) > > > > diff --git a/drivers/gpu/drm/i915/intel_dp.c > > b/drivers/gpu/drm/i915/intel_dp.c index 08834f74d396..cc431337b2dc > > 100644 > > --- a/drivers/gpu/drm/i915/intel_dp.c > > +++ b/drivers/gpu/drm/i915/intel_dp.c > > @@ -4252,19 +4252,35 @@ static void > > intel_dp_handle_test_request(struct intel_dp *intel_dp) } > > > > static void > > +intel_edp_wait_PSR_exit(struct intel_dp *intel_dp) { > > + struct drm_device *dev = intel_dp_to_dev(intel_dp); > > + struct drm_i915_private *dev_priv = dev->dev_private; > > + u32 srd_status, count = 100; > > + > > + while (count--) { > > + srd_status = I915_READ(EDP_PSR_STATUS_CTL); > > + > > + if ((srd_status & EDP_PSR_STATUS_SENDING_TP1) || > > + (srd_status & EDP_PSR_STATUS_SENDING_TP2_TP3) || > > + (srd_status & EDP_PSR_STATUS_SENDING_IDLE) || > > + (srd_status & EDP_PSR_STATUS_AUX_SENDING)) { > > + usleep_range(100, 150); > > + } else > > + return; > > + } > > +} > > + > > +static void > > intel_dp_check_link_status(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); > > + struct drm_i915_private *dev_priv = dev->dev_private; > > u8 link_status[DP_LINK_STATUS_SIZE]; > > > > 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; > > > > @@ -4278,6 +4294,14 @@ static void intel_dp_handle_test_request(struct > > intel_dp *intel_dp) > > if (!intel_dp_link_params_valid(intel_dp)) > > return; > > > > + if (is_edp(intel_dp) && dev_priv->psr.enabled) > > + intel_edp_wait_PSR_exit(intel_dp); > > + > > + if (!intel_dp_get_link_status(intel_dp, link_status)) { > > + DRM_ERROR("Failed to get link status\n"); > > + return; > > + } > > + > > /* 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", > > -- > > 1.7.9.5 > > > > _______________________________________________ > > Intel-gfx mailing list > > Intel-gfx@lists.freedesktop.org > > https://lists.freedesktop.org/mailman/listinfo/intel-gfx > > -- > Ville Syrjälä > Intel OTC -- Ville Syrjälä Intel OTC _______________________________________________ Intel-gfx mailing list Intel-gfx@lists.freedesktop.org https://lists.freedesktop.org/mailman/listinfo/intel-gfx
