Commit 7d4ecf37 authored by Dave Airlie's avatar Dave Airlie
Browse files

Merge tag 'drm-intel-next-fixes-2024-07-18' of... 

Merge tag 'drm-intel-next-fixes-2024-07-18' of https://gitlab.freedesktop.org/drm/i915/kernel

 into drm-next

- Reset intel_dp->link_trained before retraining the link [dp] (Imre Deak)
- Don't switch the LTTPR mode on an active link [dp] (Imre Deak)

Signed-off-by: default avatarDave Airlie <airlied@redhat.com>
From: Tvrtko Ursulin <tursulin@igalia.com>
Link: https://patchwork.freedesktop.org/patch/msgid/ZpjgtowjpUZoHvrl@linux
parents 478a5270 509580fa

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

+2 −0
Original line number Diff line number Diff line
@@ -5314,6 +5314,8 @@ static int intel_dp_retrain_link(struct intel_encoder *encoder, 
		const struct intel_crtc_state *crtc_state =

			to_intel_crtc_state(crtc->base.state);



		intel_dp->link_trained = false;



		intel_dp_check_frl_training(intel_dp);

		intel_dp_pcon_dsc_configure(intel_dp, crtc_state);

		intel_dp_start_link_train(NULL, intel_dp, crtc_state);

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

+48 −7
Original line number Diff line number Diff line
@@ -117,10 +117,24 @@ intel_dp_set_lttpr_transparent_mode(struct intel_dp *intel_dp, bool enable) 
	return drm_dp_dpcd_write(&intel_dp->aux, DP_PHY_REPEATER_MODE, &val, 1) == 1;

}



static int intel_dp_init_lttpr(struct intel_dp *intel_dp, const u8 dpcd[DP_RECEIVER_CAP_SIZE])

static bool intel_dp_lttpr_transparent_mode_enabled(struct intel_dp *intel_dp)

{

	return intel_dp->lttpr_common_caps[DP_PHY_REPEATER_MODE -

					   DP_LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV] ==

		DP_PHY_REPEATER_MODE_TRANSPARENT;

}



/*

 * Read the LTTPR common capabilities and switch the LTTPR PHYs to

 * non-transparent mode if this is supported. Preserve the

 * transparent/non-transparent mode on an active link.

 *

 * Return the number of detected LTTPRs in non-transparent mode or 0 if the

 * LTTPRs are in transparent mode or the detection failed.

 */

static int intel_dp_init_lttpr_phys(struct intel_dp *intel_dp, const u8 dpcd[DP_RECEIVER_CAP_SIZE])

{

	int lttpr_count;

	int i;



	if (!intel_dp_read_lttpr_common_caps(intel_dp, dpcd))

		return 0;
@@ -134,6 +148,19 @@ static int intel_dp_init_lttpr(struct intel_dp *intel_dp, const u8 dpcd[DP_RECEI 
	if (lttpr_count == 0)

		return 0;



	/*

	 * Don't change the mode on an active link, to prevent a loss of link

	 * synchronization. See DP Standard v2.0 3.6.7. about the LTTPR

	 * resetting its internal state when the mode is changed from

	 * non-transparent to transparent.

	 */

	if (intel_dp->link_trained) {

		if (lttpr_count < 0 || intel_dp_lttpr_transparent_mode_enabled(intel_dp))

			goto out_reset_lttpr_count;



		return lttpr_count;

	}



	/*

	 * See DP Standard v2.0 3.6.6.1. about the explicit disabling of

	 * non-transparent mode and the disable->enable non-transparent mode
@@ -154,11 +181,25 @@ static int intel_dp_init_lttpr(struct intel_dp *intel_dp, const u8 dpcd[DP_RECEI 
		       "Switching to LTTPR non-transparent LT mode failed, fall-back to transparent mode\n");



		intel_dp_set_lttpr_transparent_mode(intel_dp, true);



		goto out_reset_lttpr_count;

	}



	return lttpr_count;



out_reset_lttpr_count:

	intel_dp_reset_lttpr_count(intel_dp);



	return 0;

}



static int intel_dp_init_lttpr(struct intel_dp *intel_dp, const u8 dpcd[DP_RECEIVER_CAP_SIZE])

{

	int lttpr_count;

	int i;



	lttpr_count = intel_dp_init_lttpr_phys(intel_dp, dpcd);



	for (i = 0; i < lttpr_count; i++)

		intel_dp_read_lttpr_phy_caps(intel_dp, dpcd, DP_PHY_LTTPR(i));
@@ -1482,10 +1523,10 @@ void intel_dp_start_link_train(struct intel_atomic_state *state, 
	struct intel_digital_port *dig_port = dp_to_dig_port(intel_dp);

	struct intel_encoder *encoder = &dig_port->base;

	bool passed;



	/*

	 * TODO: Reiniting LTTPRs here won't be needed once proper connector

	 * HW state readout is added.

	 * Reinit the LTTPRs here to ensure that they are switched to

	 * non-transparent mode. During an earlier LTTPR detection this

	 * could've been prevented by an active link.

	 */

	int lttpr_count = intel_dp_init_lttpr_and_dprx_caps(intel_dp);