Quoting Kuogee Hsieh (2021-07-06 10:20:15) > Reduce link rate and re start link training if link training 1 > failed due to loss of clock recovery done to fix Link Layer > CTS case 4.3.1.7. Also only update voltage and pre-emphasis > swing level after link training started to fix Link Layer CTS > case 4.3.1.6. > > Signed-off-by: Kuogee Hsieh <khsieh@xxxxxxxxxxxxxx> > --- > drivers/gpu/drm/msm/dp/dp_ctrl.c | 86 ++++++++++++++++++++++++++-------------- > 1 file changed, 56 insertions(+), 30 deletions(-) > > diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c > index 27fb0f0..6f8443d 100644 > --- a/drivers/gpu/drm/msm/dp/dp_ctrl.c > +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c > @@ -83,13 +83,6 @@ struct dp_ctrl_private { > struct completion video_comp; > }; > > -struct dp_cr_status { > - u8 lane_0_1; > - u8 lane_2_3; > -}; > - > -#define DP_LANE0_1_CR_DONE 0x11 > - > static int dp_aux_link_configure(struct drm_dp_aux *aux, > struct dp_link_info *link) > { > @@ -1080,7 +1073,7 @@ static int dp_ctrl_read_link_status(struct dp_ctrl_private *ctrl, > } > > static int dp_ctrl_link_train_1(struct dp_ctrl_private *ctrl, > - struct dp_cr_status *cr, int *training_step) > + u8 *cr, int *training_step) > { > int tries, old_v_level, ret = 0; > u8 link_status[DP_LINK_STATUS_SIZE]; > @@ -1109,8 +1102,8 @@ static int dp_ctrl_link_train_1(struct dp_ctrl_private *ctrl, > if (ret) > return ret; > > - cr->lane_0_1 = link_status[0]; > - cr->lane_2_3 = link_status[1]; > + cr[0] = link_status[0]; > + cr[1] = link_status[1]; > > if (drm_dp_clock_recovery_ok(link_status, > ctrl->link->link_params.num_lanes)) { > @@ -1188,7 +1181,7 @@ static void dp_ctrl_clear_training_pattern(struct dp_ctrl_private *ctrl) > } > > static int dp_ctrl_link_train_2(struct dp_ctrl_private *ctrl, > - struct dp_cr_status *cr, int *training_step) > + u8 *cr, int *training_step) > { > int tries = 0, ret = 0; > char pattern; > @@ -1204,10 +1197,6 @@ static int dp_ctrl_link_train_2(struct dp_ctrl_private *ctrl, > else > pattern = DP_TRAINING_PATTERN_2; > > - ret = dp_ctrl_update_vx_px(ctrl); > - if (ret) > - return ret; > - > ret = dp_catalog_ctrl_set_pattern(ctrl->catalog, pattern); > if (ret) > return ret; > @@ -1220,8 +1209,8 @@ static int dp_ctrl_link_train_2(struct dp_ctrl_private *ctrl, > ret = dp_ctrl_read_link_status(ctrl, link_status); > if (ret) > return ret; > - cr->lane_0_1 = link_status[0]; > - cr->lane_2_3 = link_status[1]; > + cr[0] = link_status[0]; > + cr[1] = link_status[1]; > > if (drm_dp_channel_eq_ok(link_status, > ctrl->link->link_params.num_lanes)) { > @@ -1241,7 +1230,7 @@ static int dp_ctrl_link_train_2(struct dp_ctrl_private *ctrl, > static int dp_ctrl_reinitialize_mainlink(struct dp_ctrl_private *ctrl); > > static int dp_ctrl_link_train(struct dp_ctrl_private *ctrl, > - struct dp_cr_status *cr, int *training_step) > + u8 *cr, int *training_step) > { > int ret = 0; > u8 encoding = DP_SET_ANSI_8B10B; > @@ -1282,7 +1271,7 @@ static int dp_ctrl_link_train(struct dp_ctrl_private *ctrl, > } > > static int dp_ctrl_setup_main_link(struct dp_ctrl_private *ctrl, > - struct dp_cr_status *cr, int *training_step) > + u8 *cr, int *training_step) > { > int ret = 0; > > @@ -1496,14 +1485,14 @@ static int dp_ctrl_deinitialize_mainlink(struct dp_ctrl_private *ctrl) > static int dp_ctrl_link_maintenance(struct dp_ctrl_private *ctrl) > { > int ret = 0; > - struct dp_cr_status cr; > + u8 cr_status[2]; > int training_step = DP_TRAINING_NONE; > > dp_ctrl_push_idle(&ctrl->dp_ctrl); > > ctrl->dp_ctrl.pixel_rate = ctrl->panel->dp_mode.drm_mode.clock; > > - ret = dp_ctrl_setup_main_link(ctrl, &cr, &training_step); > + ret = dp_ctrl_setup_main_link(ctrl, cr_status, &training_step); > if (ret) > goto end; Do we need to extract the link status information from deep in these functions? Why not read it again when we need to? > > @@ -1634,6 +1623,41 @@ void dp_ctrl_handle_sink_request(struct dp_ctrl *dp_ctrl) > } > } > > +static bool dp_ctrl_any_lane_cr_done(struct dp_ctrl_private *ctrl, > + u8 *cr_status) > + > +{ > + int i; > + u8 status; > + int lane = ctrl->link->link_params.num_lanes; > + > + for (i = 0; i < lane; i++) { > + status = cr_status[i / 2]; > + status >>= ((i % 2) * 4); > + if (status & DP_LANE_CR_DONE) > + return true; > + } > + > + return false; > +} > + > +static bool dp_ctrl_any_lane_cr_lose(struct dp_ctrl_private *ctrl, > + u8 *cr_status) > +{ > + int i; > + u8 status; > + int lane = ctrl->link->link_params.num_lanes; > + > + for (i = 0; i < lane; i++) { > + status = cr_status[i / 2]; > + status >>= ((i % 2) * 4); > + if (!(status & DP_LANE_CR_DONE)) > + return true; > + } > + > + return false; > +} Why not use !drm_dp_clock_recovery_ok() for dp_ctrl_any_lane_cr_lose()? And then move dp_ctrl_any_lane_cr_done() next to drm_dp_clock_recovery_ok() and call it drm_dp_clock_recovery_any_ok()? > + > int dp_ctrl_on_link(struct dp_ctrl *dp_ctrl) > { > int rc = 0; > @@ -1641,7 +1665,7 @@ int dp_ctrl_on_link(struct dp_ctrl *dp_ctrl) > u32 rate = 0; > int link_train_max_retries = 5; > u32 const phy_cts_pixel_clk_khz = 148500; > - struct dp_cr_status cr; > + u8 cr_status[2]; > unsigned int training_step; > > if (!dp_ctrl) > @@ -1681,19 +1705,18 @@ int dp_ctrl_on_link(struct dp_ctrl *dp_ctrl) > } > > training_step = DP_TRAINING_NONE; > - rc = dp_ctrl_setup_main_link(ctrl, &cr, &training_step); > + rc = dp_ctrl_setup_main_link(ctrl, cr_status, &training_step); > if (rc == 0) { > /* training completed successfully */ > break; > } else if (training_step == DP_TRAINING_1) { > /* link train_1 failed */ > - if (!dp_catalog_link_is_connected(ctrl->catalog)) { > + if (!dp_catalog_link_is_connected(ctrl->catalog)) > break; > - } > > rc = dp_ctrl_link_rate_down_shift(ctrl); > if (rc < 0) { /* already in RBR = 1.6G */ > - if (cr.lane_0_1 & DP_LANE0_1_CR_DONE) { > + if (dp_ctrl_any_lane_cr_done(ctrl, cr_status)) { > /* > * some lanes are ready, > * reduce lane number > @@ -1709,12 +1732,15 @@ int dp_ctrl_on_link(struct dp_ctrl *dp_ctrl) > } > } > } else if (training_step == DP_TRAINING_2) { > - /* link train_2 failed, lower lane rate */ > - if (!dp_catalog_link_is_connected(ctrl->catalog)) { > + /* link train_2 failed */ > + if (!dp_catalog_link_is_connected(ctrl->catalog)) > break; > - } > > - rc = dp_ctrl_link_lane_down_shift(ctrl); > + if (dp_ctrl_any_lane_cr_lose(ctrl, cr_status)) > + rc = dp_ctrl_link_rate_down_shift(ctrl); > + else > + rc = dp_ctrl_link_lane_down_shift(ctrl); > + > if (rc < 0) { > /* end with failure */ > break; /* lane == 1 already */ > -- > The Qualcomm Innovation Center, Inc. is a member of the Code Aurora Forum, > a Linux Foundation Collaborative Project >