The sc7280 eDP sink that supports downspread will fail link training if source does not enable SSC / downspread. This change will set the downspread bit in the DP sink if supported and indicate SSC support to the DP PHY driver.
Signed-off-by: Sankeerth Billakanti quic_sbillaka@quicinc.com Reviewed-by: Stephen Boyd swboyd@chromium.org --- drivers/gpu/drm/msm/dp/dp_ctrl.c | 12 +++++++++++- 1 file changed, 11 insertions(+), 1 deletion(-)
diff --git a/drivers/gpu/drm/msm/dp/dp_ctrl.c b/drivers/gpu/drm/msm/dp/dp_ctrl.c index 62e75dc..a40e798 100644 --- a/drivers/gpu/drm/msm/dp/dp_ctrl.c +++ b/drivers/gpu/drm/msm/dp/dp_ctrl.c @@ -1228,7 +1228,9 @@ static int dp_ctrl_link_train(struct dp_ctrl_private *ctrl, int *training_step) { int ret = 0; + const u8 *dpcd = ctrl->panel->dpcd; u8 encoding = DP_SET_ANSI_8B10B; + u8 ssc; struct dp_link_info link_info = {0};
dp_ctrl_config_ctrl(ctrl); @@ -1238,6 +1240,12 @@ static int dp_ctrl_link_train(struct dp_ctrl_private *ctrl, link_info.capabilities = DP_LINK_CAP_ENHANCED_FRAMING;
dp_aux_link_configure(ctrl->aux, &link_info); + + if (drm_dp_max_downspread(dpcd)) { + ssc = DP_SPREAD_AMP_0_5; + drm_dp_dpcd_write(ctrl->aux, DP_DOWNSPREAD_CTRL, &ssc, 1); + } + drm_dp_dpcd_write(ctrl->aux, DP_MAIN_LINK_CHANNEL_CODING_SET, &encoding, 1);
@@ -1312,9 +1320,11 @@ static int dp_ctrl_enable_mainlink_clocks(struct dp_ctrl_private *ctrl) struct dp_io *dp_io = &ctrl->parser->io; struct phy *phy = dp_io->phy; struct phy_configure_opts_dp *opts_dp = &dp_io->phy_opts.dp; + const u8 *dpcd = ctrl->panel->dpcd;
opts_dp->lanes = ctrl->link->link_params.num_lanes; opts_dp->link_rate = ctrl->link->link_params.rate / 100; + opts_dp->ssc = drm_dp_max_downspread(dpcd); dp_ctrl_set_clock_rate(ctrl, DP_CTRL_PM, "ctrl_link", ctrl->link->link_params.rate * 1000);
@@ -1406,7 +1416,7 @@ void dp_ctrl_host_deinit(struct dp_ctrl *dp_ctrl)
static bool dp_ctrl_use_fixed_nvid(struct dp_ctrl_private *ctrl) { - u8 *dpcd = ctrl->panel->dpcd; + const u8 *dpcd = ctrl->panel->dpcd;
/* * For better interop experience, used a fixed NVID=0x8000