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drm/msm/dp: Enable downspread for supported DP sinks

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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>
Link: https://lore.kernel.org/r/1635839325-401-5-git-send-email-quic_sbillaka@quicinc.com
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>
This commit is contained in:
Sankeerth Billakanti 2021-11-02 13:18:44 +05:30 committed by Rob Clark
parent 447a39f4e8
commit 34f3b16575
1 changed files with 11 additions and 1 deletions
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12
drivers/gpu/drm/msm/dp/dp_ctrl.c
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@ -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