Commit c032d846 authored by Sean Anderson's avatar Sean Anderson Committed by Tomi Valkeinen
Browse files

drm: zynqmp_dp: Adjust training values per-lane 



The feedback we get from the DPRX is per-lane. Make changes using this
information, instead of picking the maximum values from all lanes. This
results in more-consistent training on marginal links.

Signed-off-by: default avatarSean Anderson <sean.anderson@linux.dev>
Reviewed-by: default avatarTomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Signed-off-by: default avatarTomi Valkeinen <tomi.valkeinen@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20240423171859.3953024-5-sean.anderson@linux.dev
parent 25af9c1a

drivers/gpu/drm/xlnx/zynqmp_dp.c

+8 −15
Original line number Diff line number Diff line
@@ -606,19 +606,12 @@ static void zynqmp_dp_adjust_train(struct zynqmp_dp *dp, 
				   u8 link_status[DP_LINK_STATUS_SIZE])

{

	u8 *train_set = dp->train_set;

	u8 voltage = 0, preemphasis = 0;

	u8 i;



	for (i = 0; i < dp->mode.lane_cnt; i++) {

		u8 v = drm_dp_get_adjust_request_voltage(link_status, i);

		u8 p = drm_dp_get_adjust_request_pre_emphasis(link_status, i);



		if (v > voltage)

			voltage = v;



		if (p > preemphasis)

			preemphasis = p;

	}

		u8 voltage = drm_dp_get_adjust_request_voltage(link_status, i);

		u8 preemphasis =

			drm_dp_get_adjust_request_pre_emphasis(link_status, i);



		if (voltage >= DP_TRAIN_VOLTAGE_SWING_LEVEL_3)

			voltage |= DP_TRAIN_MAX_SWING_REACHED;
@@ -626,9 +619,9 @@ static void zynqmp_dp_adjust_train(struct zynqmp_dp *dp, 
		if (preemphasis >= DP_TRAIN_PRE_EMPH_LEVEL_2)

			preemphasis |= DP_TRAIN_MAX_PRE_EMPHASIS_REACHED;



	for (i = 0; i < dp->mode.lane_cnt; i++)

		train_set[i] = voltage | preemphasis;

	}

}



/**

 * zynqmp_dp_update_vs_emph - Update the training values