> -----Original Message----- > From: Intel-gfx <[email protected]> On Behalf Of Imre > Deak > Sent: Friday, July 12, 2024 7:27 PM > To: [email protected] > Cc: Nautiyal, Ankit K <[email protected]>; Ville Syrjälä > <[email protected]> > Subject: [PATCH 1/3] drm/i915/dp: Retrain SST links via a modeset commit > > Instead of direct calls of the link training functions, use a modeset commit > to retrain a DP link in SST mode, similarly to how this is done in DP-MST > mode. Originally the current way was chosen presumedly, because there > wasn't a well-established way in place for the driver to do an internal (vs. > userspace/kernel client) commit. Since then such internal commits became a > common place (initial-, HDMI/TC link reset commit), so there is no reason to > handle the DP-SST link-retraining case differently. > > At the end of the current sequence the HW reported a FIFO underrun - > without other issues visible to users - because during retraining the link's > encoder/port was disabled/re-enabled without also disabling/re-enabling > the corresponding pipe/transcoder (as required by the spec); the > corresponding underrun error message was suppressed as a known issue. > Based on Ankit's test on DG2 the underrun error was still reported as it got > detected with some (vblank) delay wrt. other platforms. Switching to a > modeset commit resolves these underrun related issues. > > Cc: Ankit Nautiyal <[email protected]> > Cc: Ville Syrjälä <[email protected]> > Signed-off-by: Imre Deak <[email protected]>
LGTM, Reviewed-by: Suraj Kandpal <[email protected]> > --- > drivers/gpu/drm/i915/display/intel_dp.c | 67 ++++--------------------- > 1 file changed, 9 insertions(+), 58 deletions(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_dp.c > b/drivers/gpu/drm/i915/display/intel_dp.c > index d4b1b18453dca..f83128ac60756 100644 > --- a/drivers/gpu/drm/i915/display/intel_dp.c > +++ b/drivers/gpu/drm/i915/display/intel_dp.c > @@ -5242,8 +5242,6 @@ static int intel_dp_retrain_link(struct > intel_encoder *encoder, { > struct drm_i915_private *dev_priv = to_i915(encoder->base.dev); > struct intel_dp *intel_dp = enc_to_intel_dp(encoder); > - struct intel_crtc *crtc; > - bool mst_output = false; > u8 pipe_mask; > int ret; > > @@ -5272,64 +5270,17 @@ static int intel_dp_retrain_link(struct > intel_encoder *encoder, > encoder->base.base.id, encoder->base.name, > str_yes_no(intel_dp->link.force_retrain)); > > - for_each_intel_crtc_in_pipe_mask(&dev_priv->drm, crtc, pipe_mask) > { > - const struct intel_crtc_state *crtc_state = > - to_intel_crtc_state(crtc->base.state); > + ret = intel_modeset_commit_pipes(dev_priv, pipe_mask, ctx); > + if (ret == -EDEADLK) > + return ret; > > - if (intel_crtc_has_type(crtc_state, INTEL_OUTPUT_DP_MST)) { > - mst_output = true; > - break; > - } > + intel_dp->link.force_retrain = false; > > - /* Suppress underruns caused by re-training */ > - intel_set_cpu_fifo_underrun_reporting(dev_priv, crtc->pipe, > false); > - if (crtc_state->has_pch_encoder) > - intel_set_pch_fifo_underrun_reporting(dev_priv, > - > intel_crtc_pch_transcoder(crtc), false); > - } > - > - /* TODO: use a modeset for SST as well. */ > - if (mst_output) { > - ret = intel_modeset_commit_pipes(dev_priv, pipe_mask, > ctx); > - > - if (ret && ret != -EDEADLK) > - drm_dbg_kms(&dev_priv->drm, > - "[ENCODER:%d:%s] link retraining failed: > %pe\n", > - encoder->base.base.id, encoder- > >base.name, > - ERR_PTR(ret)); > - > - goto out; > - } > - > - for_each_intel_crtc_in_pipe_mask(&dev_priv->drm, crtc, pipe_mask) > { > - const struct intel_crtc_state *crtc_state = > - to_intel_crtc_state(crtc->base.state); > - > - intel_dp->link_trained = false; > - > - intel_dp_check_frl_training(intel_dp); > - intel_dp_pcon_dsc_configure(intel_dp, crtc_state); > - intel_dp_start_link_train(NULL, intel_dp, crtc_state); > - intel_dp_stop_link_train(intel_dp, crtc_state); > - break; > - } > - > - for_each_intel_crtc_in_pipe_mask(&dev_priv->drm, crtc, pipe_mask) > { > - const struct intel_crtc_state *crtc_state = > - to_intel_crtc_state(crtc->base.state); > - > - /* Keep underrun reporting disabled until things are stable > */ > - intel_crtc_wait_for_next_vblank(crtc); > - > - intel_set_cpu_fifo_underrun_reporting(dev_priv, crtc->pipe, > true); > - if (crtc_state->has_pch_encoder) > - intel_set_pch_fifo_underrun_reporting(dev_priv, > - > intel_crtc_pch_transcoder(crtc), true); > - } > - > -out: > - if (ret != -EDEADLK) > - intel_dp->link.force_retrain = false; > + if (ret) > + drm_dbg_kms(&dev_priv->drm, > + "[ENCODER:%d:%s] link retraining failed: %pe\n", > + encoder->base.base.id, encoder->base.name, > + ERR_PTR(ret)); > > return ret; > } > -- > 2.44.2
