On Wed, 19 Apr 2023, Arun R Murthy <arun.r.murthy@xxxxxxxxx> wrote: > For 128b/132b LT prior to LT DPTX should set power state, DP channel > coding and then link rate. > > v2: added separate function to avoid code duplication(Jani N) > > Signed-off-by: Arun R Murthy <arun.r.murthy@xxxxxxxxx> RESEND for what reason? Two v2 and neither fixes https://lore.kernel.org/r/87o7nmergw.fsf@xxxxxxxxx BR, Jani. > --- > .../drm/i915/display/intel_dp_link_training.c | 62 +++++++++++++------ > 1 file changed, 44 insertions(+), 18 deletions(-) > > diff --git a/drivers/gpu/drm/i915/display/intel_dp_link_training.c b/drivers/gpu/drm/i915/display/intel_dp_link_training.c > index 6aa4ae5e7ebe..e5809cf7d0c4 100644 > --- a/drivers/gpu/drm/i915/display/intel_dp_link_training.c > +++ b/drivers/gpu/drm/i915/display/intel_dp_link_training.c > @@ -637,6 +637,37 @@ static bool intel_dp_link_max_vswing_reached(struct intel_dp *intel_dp, > return true; > } > > +static void > +intel_dp_update_downspread_ctrl(struct intel_dp *intel_dp, > + const struct intel_crtc_state *crtc_state) > +{ > + u8 link_config[2]; > + > + link_config[0] = crtc_state->vrr.flipline ? DP_MSA_TIMING_PAR_IGNORE_EN : 0; > + link_config[1] = intel_dp_is_uhbr(crtc_state) ? > + DP_SET_ANSI_128B132B : DP_SET_ANSI_8B10B; > + drm_dp_dpcd_write(&intel_dp->aux, DP_DOWNSPREAD_CTRL, link_config, 2); > +} > + > +static void > +intel_dp_update_link_bw_set(struct intel_dp *intel_dp, > + const struct intel_crtc_state *crtc_state, > + u8 link_bw, u8 rate_select) > +{ > + u8 link_config[2]; > + > + /* Write the link configuration data */ > + link_config[0] = link_bw; > + link_config[1] = crtc_state->lane_count; > + if (drm_dp_enhanced_frame_cap(intel_dp->dpcd)) > + link_config[1] |= DP_LANE_COUNT_ENHANCED_FRAME_EN; > + drm_dp_dpcd_write(&intel_dp->aux, DP_LINK_BW_SET, link_config, 2); > + /* eDP 1.4 rate select method. */ > + if (!link_bw) > + drm_dp_dpcd_write(&intel_dp->aux, DP_LINK_RATE_SET, > + &rate_select, 1); > +} > + > /* > * Prepare link training by configuring the link parameters. On DDI platforms > * also enable the port here. > @@ -647,7 +678,6 @@ intel_dp_prepare_link_train(struct intel_dp *intel_dp, > { > struct intel_encoder *encoder = &dp_to_dig_port(intel_dp)->base; > struct drm_i915_private *i915 = to_i915(encoder->base.dev); > - u8 link_config[2]; > u8 link_bw, rate_select; > > if (intel_dp->prepare_link_retrain) > @@ -686,23 +716,19 @@ intel_dp_prepare_link_train(struct intel_dp *intel_dp, > drm_dbg_kms(&i915->drm, > "[ENCODER:%d:%s] Using LINK_RATE_SET value %02x\n", > encoder->base.base.id, encoder->base.name, rate_select); > - > - /* Write the link configuration data */ > - link_config[0] = link_bw; > - link_config[1] = crtc_state->lane_count; > - if (drm_dp_enhanced_frame_cap(intel_dp->dpcd)) > - link_config[1] |= DP_LANE_COUNT_ENHANCED_FRAME_EN; > - drm_dp_dpcd_write(&intel_dp->aux, DP_LINK_BW_SET, link_config, 2); > - > - /* eDP 1.4 rate select method. */ > - if (!link_bw) > - drm_dp_dpcd_write(&intel_dp->aux, DP_LINK_RATE_SET, > - &rate_select, 1); > - > - link_config[0] = crtc_state->vrr.flipline ? DP_MSA_TIMING_PAR_IGNORE_EN : 0; > - link_config[1] = intel_dp_is_uhbr(crtc_state) ? > - DP_SET_ANSI_128B132B : DP_SET_ANSI_8B10B; > - drm_dp_dpcd_write(&intel_dp->aux, DP_DOWNSPREAD_CTRL, link_config, 2); > + if (intel_dp_is_uhbr(crtc_state)) { > + /* > + * Spec DP2.1 Section 3.5.2.16 > + * Prior to LT DPTX should set 128b/132b DP Channel coding and then set link rate > + */ > + intel_dp_update_downspread_ctrl(intel_dp, crtc_state); > + intel_dp_update_link_bw_set(intel_dp, crtc_state, link_bw, > + rate_select); > + } else { > + intel_dp_update_link_bw_set(intel_dp, crtc_state, link_bw, > + rate_select); > + intel_dp_update_downspread_ctrl(intel_dp, crtc_state); > + } > > return true; > } -- Jani Nikula, Intel Open Source Graphics Center
