Commit eb0c1757 authored by Arun R Murthy's avatar Arun R Murthy Committed by Suraj Kandpal
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drm/i915/dp: read Aux RD interval just before setting the FFE preset 



Figure 3-52: 128b132b DP DPTC LANEx_CHANNEL_EQ_DONE Sequence of
DP2.1a spec.
After reading LANEx_CHANNEL_EQ_DONE, read the FFE presets.
AUX_RD_INTERVAL and then write the new FFE presets.

v4: Read AUX_RD_INTERVAL before get/set TX FFE preset (Jani)

Co-developed-by: default avatarSrikanth V NagaVenkata <nagavenkata.srikanth.v@intel.com>
Signed-off-by: default avatarArun R Murthy <arun.r.murthy@intel.com>
Reviewed-by: default avatarSuraj Kandpal <suraj.kandpal@intel.com>
Signed-off-by: default avatarSuraj Kandpal <suraj.kandpal@intel.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20241011045825.2629469-1-arun.r.murthy@intel.com
parent af02ee4f

drivers/gpu/drm/i915/display/intel_dp_link_training.c

+8 −7
Original line number Diff line number Diff line
@@ -1419,12 +1419,6 @@ intel_dp_128b132b_lane_eq(struct intel_dp *intel_dp, 
	for (try = 0; try < max_tries; try++) {

		fsleep(delay_us);



		/*

		 * The delay may get updated. The transmitter shall read the

		 * delay before link status during link training.

		 */

		delay_us = drm_dp_128b132b_read_aux_rd_interval(&intel_dp->aux);



		if (drm_dp_dpcd_read_link_status(&intel_dp->aux, link_status) < 0) {

			lt_err(intel_dp, DP_PHY_DPRX, "Failed to read link status\n");

			return false;
@@ -1451,8 +1445,15 @@ intel_dp_128b132b_lane_eq(struct intel_dp *intel_dp, 
		if (time_after(jiffies, deadline))

			timeout = true; /* try one last time after deadline */



		/* Update signal levels and training set as requested. */

		/*

		 * During LT, Tx shall read AUX_RD_INTERVAL just before writing the new FFE

		 * presets.

		 */

		delay_us = drm_dp_128b132b_read_aux_rd_interval(&intel_dp->aux);



		intel_dp_get_adjust_train(intel_dp, crtc_state, DP_PHY_DPRX, link_status);



		/* Update signal levels and training set as requested. */

		if (!intel_dp_update_link_train(intel_dp, crtc_state, DP_PHY_DPRX)) {

			lt_err(intel_dp, DP_PHY_DPRX, "Failed to update TX FFE settings\n");

			return false;