drivers/gpu/drm/nouveau/nouveau_dp.c - linux/kernel/git/torvalds/linux - Git at Google

 /*
  * Copyright 2009 Red Hat Inc.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
  * to deal in the Software without restriction, including without limitation
  * the rights to use, copy, modify, merge, publish, distribute, sublicense,
  * and/or sell copies of the Software, and to permit persons to whom the
  * Software is furnished to do so, subject to the following conditions:
  *
  * The above copyright notice and this permission notice shall be included in
  * all copies or substantial portions of the Software.
  *
  * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
  * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
  * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
  * THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
  * OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
  * ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
  * OTHER DEALINGS IN THE SOFTWARE.
  *
  * Authors: Ben Skeggs
  */

 #include <drm/display/drm_dp_helper.h>

 #include "nouveau_drv.h"
 #include "nouveau_connector.h"
 #include "nouveau_encoder.h"
 #include "nouveau_crtc.h"

 #include <nvif/if0011.h>

 MODULE_PARM_DESC(mst, "Enable DisplayPort multi-stream (default: enabled)");
 static int nouveau_mst = 1;
 module_param_named(mst, nouveau_mst, int, 0400);

 static bool
 nouveau_dp_has_sink_count(struct drm_connector *connector,
 			  struct nouveau_encoder *outp)
 {
 	return drm_dp_read_sink_count_cap(connector, outp->dp.dpcd, &outp->dp.desc);
 }

 static bool
 nouveau_dp_probe_lttpr(struct nouveau_encoder *outp)
 {
 	u8 rev, size = sizeof(rev);
 	int ret;

 	ret = nvif_outp_dp_aux_xfer(&outp->outp, DP_AUX_NATIVE_READ, &size,
 				    DP_LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV,
 				    &rev);
 	if (ret || size < sizeof(rev) || rev < 0x14)
 		return false;

 	return true;
 }

 static enum drm_connector_status
 nouveau_dp_probe_dpcd(struct nouveau_connector *nv_connector,
 		      struct nouveau_encoder *outp)
 {
 	struct drm_connector *connector = &nv_connector->base;
 	struct drm_dp_aux *aux = &nv_connector->aux;
 	struct nv50_mstm *mstm = NULL;
 	enum drm_connector_status status = connector_status_disconnected;
 	int ret;
 	u8 *dpcd = outp->dp.dpcd;

 	outp->dp.lttpr.nr = 0;
 	outp->dp.rate_nr  = 0;
 	outp->dp.link_nr  = 0;
 	outp->dp.link_bw  = 0;

 	if (connector->connector_type != DRM_MODE_CONNECTOR_eDP &&
 	    nouveau_dp_probe_lttpr(outp) &&
 	    !drm_dp_read_dpcd_caps(aux, dpcd) &&
 	    !drm_dp_read_lttpr_common_caps(aux, dpcd, outp->dp.lttpr.caps)) {
 		int nr = drm_dp_lttpr_count(outp->dp.lttpr.caps);

 		if (nr) {
 			drm_dp_dpcd_writeb(aux, DP_PHY_REPEATER_MODE,
 						DP_PHY_REPEATER_MODE_TRANSPARENT);

 			if (nr > 0) {
 				ret = drm_dp_dpcd_writeb(aux, DP_PHY_REPEATER_MODE,
 							      DP_PHY_REPEATER_MODE_NON_TRANSPARENT);
 				if (ret != 1) {
 					drm_dp_dpcd_writeb(aux, DP_PHY_REPEATER_MODE,
 								DP_PHY_REPEATER_MODE_TRANSPARENT);
 				} else {
 					outp->dp.lttpr.nr = nr;
 				}
 			}
 		}
 	}

 	ret = drm_dp_read_dpcd_caps(aux, dpcd);
 	if (ret < 0)
 		goto out;

 	outp->dp.link_nr = dpcd[DP_MAX_LANE_COUNT] & DP_MAX_LANE_COUNT_MASK;
 	if (outp->dcb->dpconf.link_nr < outp->dp.link_nr)
 		outp->dp.link_nr = outp->dcb->dpconf.link_nr;

 	if (outp->dp.lttpr.nr) {
 		int links = drm_dp_lttpr_max_lane_count(outp->dp.lttpr.caps);

 		if (links && links < outp->dp.link_nr)
 			outp->dp.link_nr = links;
 	}

 	if (connector->connector_type == DRM_MODE_CONNECTOR_eDP && dpcd[DP_DPCD_REV] >= 0x13) {
 		__le16 rates[DP_MAX_SUPPORTED_RATES];

 		ret = drm_dp_dpcd_read(aux, DP_SUPPORTED_LINK_RATES, rates, sizeof(rates));
 		if (ret == sizeof(rates)) {
 			for (int i = 0; i < ARRAY_SIZE(rates); i++) {
 				u32 rate = (le16_to_cpu(rates[i]) * 200) / 10;
 				int j;

 				if (!rate)
 					break;

 				for (j = 0; j < outp->dp.rate_nr; j++) {
 					if (rate > outp->dp.rate[j].rate) {
 						for (int k = outp->dp.rate_nr; k > j; k--)
 							outp->dp.rate[k] = outp->dp.rate[k - 1];
 						break;
 					}
 				}

 				outp->dp.rate[j].dpcd = i;
 				outp->dp.rate[j].rate = rate;
 				outp->dp.rate_nr++;
 			}
 		}
 	}

 	if (!outp->dp.rate_nr) {
 		const u32 rates[] = { 810000, 540000, 270000, 162000 };
 		u32 max_rate = dpcd[DP_MAX_LINK_RATE] * 27000;

 		if (outp->dp.lttpr.nr) {
 			int rate = drm_dp_lttpr_max_link_rate(outp->dp.lttpr.caps);

 			if (rate && rate < max_rate)
 				max_rate = rate;
 		}

 		max_rate = min_t(int, max_rate, outp->dcb->dpconf.link_bw);

 		for (int i = 0; i < ARRAY_SIZE(rates); i++) {
 			if (rates[i] <= max_rate) {
 				outp->dp.rate[outp->dp.rate_nr].dpcd = -1;
 				outp->dp.rate[outp->dp.rate_nr].rate = rates[i];
 				outp->dp.rate_nr++;
 			}
 		}

 		if (WARN_ON(!outp->dp.rate_nr))
 			goto out;
 	}

 	ret = nvif_outp_dp_rates(&outp->outp, outp->dp.rate, outp->dp.rate_nr);
 	if (ret)
 		goto out;

 	for (int i = 0; i < outp->dp.rate_nr; i++) {
 		u32 link_bw = outp->dp.rate[i].rate;

 		if (link_bw > outp->dp.link_bw)
 			outp->dp.link_bw = link_bw;
 	}

 	ret = drm_dp_read_desc(aux, &outp->dp.desc, drm_dp_is_branch(dpcd));
 	if (ret < 0)
 		goto out;

 	if (nouveau_mst) {
 		mstm = outp->dp.mstm;
 		if (mstm)
 			mstm->can_mst = drm_dp_read_mst_cap(aux, dpcd);
 	}

 	if (nouveau_dp_has_sink_count(connector, outp)) {
 		ret = drm_dp_read_sink_count(aux);
 		if (ret < 0)
 			goto out;

 		outp->dp.sink_count = ret;

 		/*
 		 * Dongle connected, but no display. Don't bother reading
 		 * downstream port info
 		 */
 		if (!outp->dp.sink_count)
 			return connector_status_disconnected;
 	}

 	ret = drm_dp_read_downstream_info(aux, dpcd,
 					  outp->dp.downstream_ports);
 	if (ret < 0)
 		goto out;

 	status = connector_status_connected;
 out:
 	if (status != connector_status_connected) {
 		/* Clear any cached info */
 		outp->dp.sink_count = 0;
 	}
 	return status;
 }

 int
 nouveau_dp_detect(struct nouveau_connector *nv_connector,
 		  struct nouveau_encoder *nv_encoder)
 {
 	struct drm_device *dev = nv_encoder->base.base.dev;
 	struct nouveau_drm *drm = nouveau_drm(dev);
 	struct drm_connector *connector = &nv_connector->base;
 	struct nv50_mstm *mstm = nv_encoder->dp.mstm;
 	enum drm_connector_status status;
 	u8 *dpcd = nv_encoder->dp.dpcd;
 	int ret = NOUVEAU_DP_NONE, hpd;

 	/* eDP ports don't support hotplugging - so there's no point in probing eDP ports unless we
 	 * haven't probed them once before.
 	 */
 	if (connector->connector_type == DRM_MODE_CONNECTOR_eDP) {
 		if (connector->status == connector_status_connected)
 			return NOUVEAU_DP_SST;
 		else if (connector->status == connector_status_disconnected)
 			return NOUVEAU_DP_NONE;
 	}

 	// Ensure that the aux bus is enabled for probing
 	drm_dp_dpcd_set_powered(&nv_connector->aux, true);

 	mutex_lock(&nv_encoder->dp.hpd_irq_lock);
 	if (mstm) {
 		/* If we're not ready to handle MST state changes yet, just
 		 * report the last status of the connector. We'll reprobe it
 		 * once we've resumed.
 		 */
 		if (mstm->suspended) {
 			if (mstm->is_mst)
 				ret = NOUVEAU_DP_MST;
 			else if (connector->status ==
 				 connector_status_connected)
 				ret = NOUVEAU_DP_SST;

 			goto out;
 		}
 	}

 	hpd = nvif_outp_detect(&nv_encoder->outp);
 	if (hpd == NOT_PRESENT) {
 		nvif_outp_dp_aux_pwr(&nv_encoder->outp, false);
 		goto out;
 	}
 	nvif_outp_dp_aux_pwr(&nv_encoder->outp, true);

 	status = nouveau_dp_probe_dpcd(nv_connector, nv_encoder);
 	if (status == connector_status_disconnected) {
 		nvif_outp_dp_aux_pwr(&nv_encoder->outp, false);
 		goto out;
 	}

 	/* If we're in MST mode, we're done here */
 	if (mstm && mstm->can_mst && mstm->is_mst) {
 		ret = NOUVEAU_DP_MST;
 		goto out;
 	}

 	NV_DEBUG(drm, "sink dpcd version: 0x%02x\n", dpcd[DP_DPCD_REV]);
 	for (int i = 0; i < nv_encoder->dp.rate_nr; i++)
 		NV_DEBUG(drm, "sink rate %d: %d\n", i, nv_encoder->dp.rate[i].rate);

 	NV_DEBUG(drm, "encoder: %dx%d\n", nv_encoder->dcb->dpconf.link_nr,
 					  nv_encoder->dcb->dpconf.link_bw);
 	NV_DEBUG(drm, "maximum: %dx%d\n", nv_encoder->dp.link_nr,
 					  nv_encoder->dp.link_bw);

 	if (mstm && mstm->can_mst) {
 		ret = nv50_mstm_detect(nv_encoder);
 		if (ret == 1) {
 			ret = NOUVEAU_DP_MST;
 			goto out;
 		} else if (ret != 0) {
 			nvif_outp_dp_aux_pwr(&nv_encoder->outp, false);
 			goto out;
 		}
 	}
 	ret = NOUVEAU_DP_SST;

 out:
 	if (mstm && !mstm->suspended && ret != NOUVEAU_DP_MST)
 		nv50_mstm_remove(mstm);

 	/* GSP doesn't like when we try to do aux transactions on a port it considers disconnected,
 	 * and since we don't really have a usecase for that anyway - just disable the aux bus here
 	 * if we've decided the connector is disconnected
 	 */
 	if (ret == NOUVEAU_DP_NONE)
 		drm_dp_dpcd_set_powered(&nv_connector->aux, false);

 	mutex_unlock(&nv_encoder->dp.hpd_irq_lock);
 	return ret;
 }

 void
 nouveau_dp_power_down(struct nouveau_encoder *outp)
 {
 	struct drm_dp_aux *aux = &outp->conn->aux;
 	int ret;
 	u8 pwr;

 	mutex_lock(&outp->dp.hpd_irq_lock);

 	ret = drm_dp_dpcd_readb(aux, DP_SET_POWER, &pwr);
 	if (ret == 1) {
 		pwr &= ~DP_SET_POWER_MASK;
 		pwr |=  DP_SET_POWER_D3;
 		drm_dp_dpcd_writeb(aux, DP_SET_POWER, pwr);
 	}

 	outp->dp.lt.nr = 0;
 	mutex_unlock(&outp->dp.hpd_irq_lock);
 }

 static bool
 nouveau_dp_train_link(struct nouveau_encoder *outp, bool retrain)
 {
 	struct drm_dp_aux *aux = &outp->conn->aux;
 	bool post_lt = false;
 	int ret, retries = 0;

 	if ( (outp->dp.dpcd[DP_MAX_LANE_COUNT] & 0x20) &&
 	    !(outp->dp.dpcd[DP_MAX_DOWNSPREAD] & DP_TPS4_SUPPORTED))
 	    post_lt = true;

 retry:
 	ret = nvif_outp_dp_train(&outp->outp, outp->dp.dpcd,
 					      outp->dp.lttpr.nr,
 					      outp->dp.lt.nr,
 					      outp->dp.lt.bw,
 					      outp->dp.lt.mst,
 					      post_lt,
 					      retrain);
 	if (ret)
 		return false;

 	if (post_lt) {
 		u8 stat[DP_LINK_STATUS_SIZE];
 		u8 prev[2];
 		u8 time = 0, adjusts = 0, tmp;

 		ret = drm_dp_dpcd_read_phy_link_status(aux, DP_PHY_DPRX, stat);
 		if (ret)
 			return false;

 		for (;;) {
 			if (!drm_dp_channel_eq_ok(stat, outp->dp.lt.nr)) {
 				ret = 1;
 				break;
 			}

 			if (!(stat[2] & 0x02))
 				break;

 			msleep(5);
 			time += 5;

 			memcpy(prev, &stat[4], sizeof(prev));
 			ret = drm_dp_dpcd_read_phy_link_status(aux, DP_PHY_DPRX, stat);
 			if (ret)
 				break;

 			if (!memcmp(prev, &stat[4], sizeof(prev))) {
 				if (time > 200)
 					break;
 			} else {
 				u8 pe[4], vs[4];

 				if (adjusts++ == 6)
 					break;

 				for (int i = 0; i < outp->dp.lt.nr; i++) {
 					pe[i] = drm_dp_get_adjust_request_pre_emphasis(stat, i) >>
 							DP_TRAIN_PRE_EMPHASIS_SHIFT;
 					vs[i] = drm_dp_get_adjust_request_voltage(stat, i) >>
 							DP_TRAIN_VOLTAGE_SWING_SHIFT;
 				}

 				ret = nvif_outp_dp_drive(&outp->outp, outp->dp.lt.nr, pe, vs);
 				if (ret)
 					break;

 				time = 0;
 			}
 		}

 		if (drm_dp_dpcd_readb(aux, DP_LANE_COUNT_SET, &tmp) == 1) {
 			tmp &= ~0x20;
 			drm_dp_dpcd_writeb(aux, DP_LANE_COUNT_SET, tmp);
 		}
 	}

 	if (ret == 1 && retries++ < 3)
 		goto retry;

 	return ret == 0;
 }

 bool
 nouveau_dp_train(struct nouveau_encoder *outp, bool mst, u32 khz, u8 bpc)
 {
 	struct nouveau_drm *drm = nouveau_drm(outp->base.base.dev);
 	struct drm_dp_aux *aux = &outp->conn->aux;
 	u32 min_rate;
 	u8 pwr;
 	bool ret = true;

 	if (mst)
 		min_rate = outp->dp.link_nr * outp->dp.rate[0].rate;
 	else
 		min_rate = DIV_ROUND_UP(khz * bpc * 3, 8);

 	NV_DEBUG(drm, "%s link training (mst:%d min_rate:%d)\n",
 		 outp->base.base.name, mst, min_rate);

 	mutex_lock(&outp->dp.hpd_irq_lock);

 	if (drm_dp_dpcd_readb(aux, DP_SET_POWER, &pwr) == 1) {
 		if ((pwr & DP_SET_POWER_MASK) != DP_SET_POWER_D0) {
 			pwr &= ~DP_SET_POWER_MASK;
 			pwr |=  DP_SET_POWER_D0;
 			drm_dp_dpcd_writeb(aux, DP_SET_POWER, pwr);
 		}
 	}

 	for (int nr = outp->dp.link_nr; nr; nr >>= 1) {
 		for (int rate = 0; rate < outp->dp.rate_nr; rate++) {
 			if (outp->dp.rate[rate].rate * nr >= min_rate) {
 				outp->dp.lt.nr = nr;
 				outp->dp.lt.bw = outp->dp.rate[rate].rate;
 				outp->dp.lt.mst = mst;
 				if (nouveau_dp_train_link(outp, false))
 					goto done;
 			}
 		}
 	}

 	ret = false;
 done:
 	mutex_unlock(&outp->dp.hpd_irq_lock);
 	return ret;
 }

 static bool
 nouveau_dp_link_check_locked(struct nouveau_encoder *outp)
 {
 	u8 link_status[DP_LINK_STATUS_SIZE];

 	if (!outp || !outp->dp.lt.nr)
 		return true;

 	if (drm_dp_dpcd_read_phy_link_status(&outp->conn->aux, DP_PHY_DPRX, link_status) < 0)
 		return false;

 	if (drm_dp_channel_eq_ok(link_status, outp->dp.lt.nr))
 		return true;

 	return nouveau_dp_train_link(outp, true);
 }

 bool
 nouveau_dp_link_check(struct nouveau_connector *nv_connector)
 {
 	struct nouveau_encoder *outp = nv_connector->dp_encoder;
 	bool link_ok = true;

 	if (outp) {
 		mutex_lock(&outp->dp.hpd_irq_lock);
 		if (outp->dp.lt.nr)
 			link_ok = nouveau_dp_link_check_locked(outp);
 		mutex_unlock(&outp->dp.hpd_irq_lock);
 	}

 	return link_ok;
 }

 void
 nouveau_dp_irq(struct work_struct *work)
 {
 	struct nouveau_connector *nv_connector =
 		container_of(work, typeof(*nv_connector), irq_work);
 	struct drm_connector *connector = &nv_connector->base;
 	struct nouveau_encoder *outp = find_encoder(connector, DCB_OUTPUT_DP);
 	struct nouveau_drm *drm = nouveau_drm(outp->base.base.dev);
 	struct nv50_mstm *mstm;
 	u64 hpd = 0;
 	int ret;

 	if (!outp)
 		return;

 	mstm = outp->dp.mstm;
 	NV_DEBUG(drm, "service %s\n", connector->name);

 	mutex_lock(&outp->dp.hpd_irq_lock);

 	if (mstm && mstm->is_mst) {
 		if (!nv50_mstm_service(drm, nv_connector, mstm))
 			hpd |= NVIF_CONN_EVENT_V0_UNPLUG;
 	} else {
 		drm_dp_cec_irq(&nv_connector->aux);

 		if (nouveau_dp_has_sink_count(connector, outp)) {
 			ret = drm_dp_read_sink_count(&nv_connector->aux);
 			if (ret != outp->dp.sink_count)
 				hpd |= NVIF_CONN_EVENT_V0_PLUG;
 			if (ret >= 0)
 				outp->dp.sink_count = ret;
 		}
 	}

 	mutex_unlock(&outp->dp.hpd_irq_lock);

 	nouveau_connector_hpd(nv_connector, NVIF_CONN_EVENT_V0_IRQ | hpd);
 }

 /* TODO:
  * - Validate against the DP caps advertised by the GPU (we don't check these
  *   yet)
  */
 enum drm_mode_status
 nv50_dp_mode_valid(struct nouveau_encoder *outp,
 		   const struct drm_display_mode *mode,
 		   unsigned *out_clock)
 {
 	const unsigned int min_clock = 25000;
 	unsigned int max_rate, mode_rate, ds_max_dotclock, clock = mode->clock;
 	/* Check with the minmum bpc always, so we can advertise better modes.
 	 * In particlar not doing this causes modes to be dropped on HDR
 	 * displays as we might check with a bpc of 16 even.
 	 */
 	const u8 bpp = 6 * 3;

 	if (mode->flags & DRM_MODE_FLAG_INTERLACE && !outp->caps.dp_interlace)
 		return MODE_NO_INTERLACE;

 	if ((mode->flags & DRM_MODE_FLAG_3D_MASK) == DRM_MODE_FLAG_3D_FRAME_PACKING)
 		clock *= 2;

 	max_rate = outp->dp.link_nr * outp->dp.link_bw;
 	mode_rate = DIV_ROUND_UP(clock * bpp, 8);
 	if (mode_rate > max_rate)
 		return MODE_CLOCK_HIGH;

 	ds_max_dotclock = drm_dp_downstream_max_dotclock(outp->dp.dpcd, outp->dp.downstream_ports);
 	if (ds_max_dotclock && clock > ds_max_dotclock)
 		return MODE_CLOCK_HIGH;

 	if (clock < min_clock)
 		return MODE_CLOCK_LOW;

 	if (out_clock)
 		*out_clock = clock;

 	return MODE_OK;
 }
	/*
	* Copyright 2009 Red Hat Inc.
	*
	* Permission is hereby granted, free of charge, to any person obtaining a
	* copy of this software and associated documentation files (the "Software"),
	* to deal in the Software without restriction, including without limitation
	* the rights to use, copy, modify, merge, publish, distribute, sublicense,
	* and/or sell copies of the Software, and to permit persons to whom the
	* Software is furnished to do so, subject to the following conditions:
	*
	* The above copyright notice and this permission notice shall be included in
	* all copies or substantial portions of the Software.
	*
	* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
	* IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
	* FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
	* THE COPYRIGHT HOLDER(S) OR AUTHOR(S) BE LIABLE FOR ANY CLAIM, DAMAGES OR
	* OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE,
	* ARISING FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR
	* OTHER DEALINGS IN THE SOFTWARE.
	*
	* Authors: Ben Skeggs
	*/

	#include <drm/display/drm_dp_helper.h>

	#include "nouveau_drv.h"
	#include "nouveau_connector.h"
	#include "nouveau_encoder.h"
	#include "nouveau_crtc.h"

	#include <nvif/if0011.h>

	MODULE_PARM_DESC(mst, "Enable DisplayPort multi-stream (default: enabled)");
	static int nouveau_mst = 1;
	module_param_named(mst, nouveau_mst, int, 0400);

	static bool
	nouveau_dp_has_sink_count(struct drm_connector *connector,
	struct nouveau_encoder *outp)
	{
	return drm_dp_read_sink_count_cap(connector, outp->dp.dpcd, &outp->dp.desc);
	}

	static bool
	nouveau_dp_probe_lttpr(struct nouveau_encoder *outp)
	{
	u8 rev, size = sizeof(rev);
	int ret;

	ret = nvif_outp_dp_aux_xfer(&outp->outp, DP_AUX_NATIVE_READ, &size,
	DP_LT_TUNABLE_PHY_REPEATER_FIELD_DATA_STRUCTURE_REV,
	&rev);
	if (ret \|\| size < sizeof(rev) \|\| rev < 0x14)
	return false;

	return true;
	}

	static enum drm_connector_status
	nouveau_dp_probe_dpcd(struct nouveau_connector *nv_connector,
	struct nouveau_encoder *outp)
	{
	struct drm_connector *connector = &nv_connector->base;
	struct drm_dp_aux *aux = &nv_connector->aux;
	struct nv50_mstm *mstm = NULL;
	enum drm_connector_status status = connector_status_disconnected;
	int ret;
	u8 *dpcd = outp->dp.dpcd;

	outp->dp.lttpr.nr = 0;
	outp->dp.rate_nr = 0;
	outp->dp.link_nr = 0;
	outp->dp.link_bw = 0;

	if (connector->connector_type != DRM_MODE_CONNECTOR_eDP &&
	nouveau_dp_probe_lttpr(outp) &&
	!drm_dp_read_dpcd_caps(aux, dpcd) &&
	!drm_dp_read_lttpr_common_caps(aux, dpcd, outp->dp.lttpr.caps)) {
	int nr = drm_dp_lttpr_count(outp->dp.lttpr.caps);

	if (nr) {
	drm_dp_dpcd_writeb(aux, DP_PHY_REPEATER_MODE,
	DP_PHY_REPEATER_MODE_TRANSPARENT);

	if (nr > 0) {
	ret = drm_dp_dpcd_writeb(aux, DP_PHY_REPEATER_MODE,
	DP_PHY_REPEATER_MODE_NON_TRANSPARENT);
	if (ret != 1) {
	drm_dp_dpcd_writeb(aux, DP_PHY_REPEATER_MODE,
	DP_PHY_REPEATER_MODE_TRANSPARENT);
	} else {
	outp->dp.lttpr.nr = nr;
	}
	}
	}
	}

	ret = drm_dp_read_dpcd_caps(aux, dpcd);
	if (ret < 0)
	goto out;

	outp->dp.link_nr = dpcd[DP_MAX_LANE_COUNT] & DP_MAX_LANE_COUNT_MASK;
	if (outp->dcb->dpconf.link_nr < outp->dp.link_nr)
	outp->dp.link_nr = outp->dcb->dpconf.link_nr;

	if (outp->dp.lttpr.nr) {
	int links = drm_dp_lttpr_max_lane_count(outp->dp.lttpr.caps);

	if (links && links < outp->dp.link_nr)
	outp->dp.link_nr = links;
	}

	if (connector->connector_type == DRM_MODE_CONNECTOR_eDP && dpcd[DP_DPCD_REV] >= 0x13) {
	__le16 rates[DP_MAX_SUPPORTED_RATES];

	ret = drm_dp_dpcd_read(aux, DP_SUPPORTED_LINK_RATES, rates, sizeof(rates));
	if (ret == sizeof(rates)) {
	for (int i = 0; i < ARRAY_SIZE(rates); i++) {
	u32 rate = (le16_to_cpu(rates[i]) * 200) / 10;
	int j;

	if (!rate)
	break;

	for (j = 0; j < outp->dp.rate_nr; j++) {
	if (rate > outp->dp.rate[j].rate) {
	for (int k = outp->dp.rate_nr; k > j; k--)
	outp->dp.rate[k] = outp->dp.rate[k - 1];
	break;
	}
	}

	outp->dp.rate[j].dpcd = i;
	outp->dp.rate[j].rate = rate;
	outp->dp.rate_nr++;
	}
	}
	}

	if (!outp->dp.rate_nr) {
	const u32 rates[] = { 810000, 540000, 270000, 162000 };
	u32 max_rate = dpcd[DP_MAX_LINK_RATE] * 27000;

	if (outp->dp.lttpr.nr) {
	int rate = drm_dp_lttpr_max_link_rate(outp->dp.lttpr.caps);

	if (rate && rate < max_rate)
	max_rate = rate;
	}

	max_rate = min_t(int, max_rate, outp->dcb->dpconf.link_bw);

	for (int i = 0; i < ARRAY_SIZE(rates); i++) {
	if (rates[i] <= max_rate) {
	outp->dp.rate[outp->dp.rate_nr].dpcd = -1;
	outp->dp.rate[outp->dp.rate_nr].rate = rates[i];
	outp->dp.rate_nr++;
	}
	}

	if (WARN_ON(!outp->dp.rate_nr))
	goto out;
	}

	ret = nvif_outp_dp_rates(&outp->outp, outp->dp.rate, outp->dp.rate_nr);
	if (ret)
	goto out;

	for (int i = 0; i < outp->dp.rate_nr; i++) {
	u32 link_bw = outp->dp.rate[i].rate;

	if (link_bw > outp->dp.link_bw)
	outp->dp.link_bw = link_bw;
	}

	ret = drm_dp_read_desc(aux, &outp->dp.desc, drm_dp_is_branch(dpcd));
	if (ret < 0)
	goto out;

	if (nouveau_mst) {
	mstm = outp->dp.mstm;
	if (mstm)
	mstm->can_mst = drm_dp_read_mst_cap(aux, dpcd);
	}

	if (nouveau_dp_has_sink_count(connector, outp)) {
	ret = drm_dp_read_sink_count(aux);
	if (ret < 0)
	goto out;

	outp->dp.sink_count = ret;

	/*
	* Dongle connected, but no display. Don't bother reading
	* downstream port info
	*/
	if (!outp->dp.sink_count)
	return connector_status_disconnected;
	}

	ret = drm_dp_read_downstream_info(aux, dpcd,
	outp->dp.downstream_ports);
	if (ret < 0)
	goto out;

	status = connector_status_connected;
	out:
	if (status != connector_status_connected) {
	/* Clear any cached info */
	outp->dp.sink_count = 0;
	}
	return status;
	}

	int
	nouveau_dp_detect(struct nouveau_connector *nv_connector,
	struct nouveau_encoder *nv_encoder)
	{
	struct drm_device *dev = nv_encoder->base.base.dev;
	struct nouveau_drm *drm = nouveau_drm(dev);
	struct drm_connector *connector = &nv_connector->base;
	struct nv50_mstm *mstm = nv_encoder->dp.mstm;
	enum drm_connector_status status;
	u8 *dpcd = nv_encoder->dp.dpcd;
	int ret = NOUVEAU_DP_NONE, hpd;

	/* eDP ports don't support hotplugging - so there's no point in probing eDP ports unless we
	* haven't probed them once before.
	*/
	if (connector->connector_type == DRM_MODE_CONNECTOR_eDP) {
	if (connector->status == connector_status_connected)
	return NOUVEAU_DP_SST;
	else if (connector->status == connector_status_disconnected)
	return NOUVEAU_DP_NONE;
	}

	// Ensure that the aux bus is enabled for probing
	drm_dp_dpcd_set_powered(&nv_connector->aux, true);

	mutex_lock(&nv_encoder->dp.hpd_irq_lock);
	if (mstm) {
	/* If we're not ready to handle MST state changes yet, just
	* report the last status of the connector. We'll reprobe it
	* once we've resumed.
	*/
	if (mstm->suspended) {
	if (mstm->is_mst)
	ret = NOUVEAU_DP_MST;
	else if (connector->status ==
	connector_status_connected)
	ret = NOUVEAU_DP_SST;

	goto out;
	}
	}

	hpd = nvif_outp_detect(&nv_encoder->outp);
	if (hpd == NOT_PRESENT) {
	nvif_outp_dp_aux_pwr(&nv_encoder->outp, false);
	goto out;
	}
	nvif_outp_dp_aux_pwr(&nv_encoder->outp, true);

	status = nouveau_dp_probe_dpcd(nv_connector, nv_encoder);
	if (status == connector_status_disconnected) {
	nvif_outp_dp_aux_pwr(&nv_encoder->outp, false);
	goto out;
	}

	/* If we're in MST mode, we're done here */
	if (mstm && mstm->can_mst && mstm->is_mst) {
	ret = NOUVEAU_DP_MST;
	goto out;
	}

	NV_DEBUG(drm, "sink dpcd version: 0x%02x\n", dpcd[DP_DPCD_REV]);
	for (int i = 0; i < nv_encoder->dp.rate_nr; i++)
	NV_DEBUG(drm, "sink rate %d: %d\n", i, nv_encoder->dp.rate[i].rate);

	NV_DEBUG(drm, "encoder: %dx%d\n", nv_encoder->dcb->dpconf.link_nr,
	nv_encoder->dcb->dpconf.link_bw);
	NV_DEBUG(drm, "maximum: %dx%d\n", nv_encoder->dp.link_nr,
	nv_encoder->dp.link_bw);

	if (mstm && mstm->can_mst) {
	ret = nv50_mstm_detect(nv_encoder);
	if (ret == 1) {
	ret = NOUVEAU_DP_MST;
	goto out;
	} else if (ret != 0) {
	nvif_outp_dp_aux_pwr(&nv_encoder->outp, false);
	goto out;
	}
	}
	ret = NOUVEAU_DP_SST;

	out:
	if (mstm && !mstm->suspended && ret != NOUVEAU_DP_MST)
	nv50_mstm_remove(mstm);

	/* GSP doesn't like when we try to do aux transactions on a port it considers disconnected,
	* and since we don't really have a usecase for that anyway - just disable the aux bus here
	* if we've decided the connector is disconnected
	*/
	if (ret == NOUVEAU_DP_NONE)
	drm_dp_dpcd_set_powered(&nv_connector->aux, false);

	mutex_unlock(&nv_encoder->dp.hpd_irq_lock);
	return ret;
	}

	void
	nouveau_dp_power_down(struct nouveau_encoder *outp)
	{
	struct drm_dp_aux *aux = &outp->conn->aux;
	int ret;
	u8 pwr;

	mutex_lock(&outp->dp.hpd_irq_lock);

	ret = drm_dp_dpcd_readb(aux, DP_SET_POWER, &pwr);
	if (ret == 1) {
	pwr &= ~DP_SET_POWER_MASK;
	pwr \|= DP_SET_POWER_D3;
	drm_dp_dpcd_writeb(aux, DP_SET_POWER, pwr);
	}

	outp->dp.lt.nr = 0;
	mutex_unlock(&outp->dp.hpd_irq_lock);
	}

	static bool
	nouveau_dp_train_link(struct nouveau_encoder *outp, bool retrain)
	{
	struct drm_dp_aux *aux = &outp->conn->aux;
	bool post_lt = false;
	int ret, retries = 0;

	if ( (outp->dp.dpcd[DP_MAX_LANE_COUNT] & 0x20) &&
	!(outp->dp.dpcd[DP_MAX_DOWNSPREAD] & DP_TPS4_SUPPORTED))
	post_lt = true;

	retry:
	ret = nvif_outp_dp_train(&outp->outp, outp->dp.dpcd,
	outp->dp.lttpr.nr,
	outp->dp.lt.nr,
	outp->dp.lt.bw,
	outp->dp.lt.mst,
	post_lt,
	retrain);
	if (ret)
	return false;

	if (post_lt) {
	u8 stat[DP_LINK_STATUS_SIZE];
	u8 prev[2];
	u8 time = 0, adjusts = 0, tmp;

	ret = drm_dp_dpcd_read_phy_link_status(aux, DP_PHY_DPRX, stat);
	if (ret)
	return false;

	for (;;) {
	if (!drm_dp_channel_eq_ok(stat, outp->dp.lt.nr)) {
	ret = 1;
	break;
	}

	if (!(stat[2] & 0x02))
	break;

	msleep(5);
	time += 5;

	memcpy(prev, &stat[4], sizeof(prev));
	ret = drm_dp_dpcd_read_phy_link_status(aux, DP_PHY_DPRX, stat);
	if (ret)
	break;

	if (!memcmp(prev, &stat[4], sizeof(prev))) {
	if (time > 200)
	break;
	} else {
	u8 pe[4], vs[4];

	if (adjusts++ == 6)
	break;

	for (int i = 0; i < outp->dp.lt.nr; i++) {
	pe[i] = drm_dp_get_adjust_request_pre_emphasis(stat, i) >>
	DP_TRAIN_PRE_EMPHASIS_SHIFT;
	vs[i] = drm_dp_get_adjust_request_voltage(stat, i) >>
	DP_TRAIN_VOLTAGE_SWING_SHIFT;
	}

	ret = nvif_outp_dp_drive(&outp->outp, outp->dp.lt.nr, pe, vs);
	if (ret)
	break;

	time = 0;
	}
	}

	if (drm_dp_dpcd_readb(aux, DP_LANE_COUNT_SET, &tmp) == 1) {
	tmp &= ~0x20;
	drm_dp_dpcd_writeb(aux, DP_LANE_COUNT_SET, tmp);
	}
	}

	if (ret == 1 && retries++ < 3)
	goto retry;

	return ret == 0;
	}

	bool
	nouveau_dp_train(struct nouveau_encoder *outp, bool mst, u32 khz, u8 bpc)
	{
	struct nouveau_drm *drm = nouveau_drm(outp->base.base.dev);
	struct drm_dp_aux *aux = &outp->conn->aux;
	u32 min_rate;
	u8 pwr;
	bool ret = true;

	if (mst)
	min_rate = outp->dp.link_nr * outp->dp.rate[0].rate;
	else
	min_rate = DIV_ROUND_UP(khz * bpc * 3, 8);

	NV_DEBUG(drm, "%s link training (mst:%d min_rate:%d)\n",
	outp->base.base.name, mst, min_rate);

	mutex_lock(&outp->dp.hpd_irq_lock);

	if (drm_dp_dpcd_readb(aux, DP_SET_POWER, &pwr) == 1) {
	if ((pwr & DP_SET_POWER_MASK) != DP_SET_POWER_D0) {
	pwr &= ~DP_SET_POWER_MASK;
	pwr \|= DP_SET_POWER_D0;
	drm_dp_dpcd_writeb(aux, DP_SET_POWER, pwr);
	}
	}

	for (int nr = outp->dp.link_nr; nr; nr >>= 1) {
	for (int rate = 0; rate < outp->dp.rate_nr; rate++) {
	if (outp->dp.rate[rate].rate * nr >= min_rate) {
	outp->dp.lt.nr = nr;
	outp->dp.lt.bw = outp->dp.rate[rate].rate;
	outp->dp.lt.mst = mst;
	if (nouveau_dp_train_link(outp, false))
	goto done;
	}
	}
	}

	ret = false;
	done:
	mutex_unlock(&outp->dp.hpd_irq_lock);
	return ret;
	}

	static bool
	nouveau_dp_link_check_locked(struct nouveau_encoder *outp)
	{
	u8 link_status[DP_LINK_STATUS_SIZE];

	if (!outp \|\| !outp->dp.lt.nr)
	return true;

	if (drm_dp_dpcd_read_phy_link_status(&outp->conn->aux, DP_PHY_DPRX, link_status) < 0)
	return false;

	if (drm_dp_channel_eq_ok(link_status, outp->dp.lt.nr))
	return true;

	return nouveau_dp_train_link(outp, true);
	}

	bool
	nouveau_dp_link_check(struct nouveau_connector *nv_connector)
	{
	struct nouveau_encoder *outp = nv_connector->dp_encoder;
	bool link_ok = true;

	if (outp) {
	mutex_lock(&outp->dp.hpd_irq_lock);
	if (outp->dp.lt.nr)
	link_ok = nouveau_dp_link_check_locked(outp);
	mutex_unlock(&outp->dp.hpd_irq_lock);
	}

	return link_ok;
	}

	void
	nouveau_dp_irq(struct work_struct *work)
	{
	struct nouveau_connector *nv_connector =
	container_of(work, typeof(*nv_connector), irq_work);
	struct drm_connector *connector = &nv_connector->base;
	struct nouveau_encoder *outp = find_encoder(connector, DCB_OUTPUT_DP);
	struct nouveau_drm *drm = nouveau_drm(outp->base.base.dev);
	struct nv50_mstm *mstm;
	u64 hpd = 0;
	int ret;

	if (!outp)
	return;

	mstm = outp->dp.mstm;
	NV_DEBUG(drm, "service %s\n", connector->name);

	mutex_lock(&outp->dp.hpd_irq_lock);

	if (mstm && mstm->is_mst) {
	if (!nv50_mstm_service(drm, nv_connector, mstm))
	hpd \|= NVIF_CONN_EVENT_V0_UNPLUG;
	} else {
	drm_dp_cec_irq(&nv_connector->aux);

	if (nouveau_dp_has_sink_count(connector, outp)) {
	ret = drm_dp_read_sink_count(&nv_connector->aux);
	if (ret != outp->dp.sink_count)
	hpd \|= NVIF_CONN_EVENT_V0_PLUG;
	if (ret >= 0)
	outp->dp.sink_count = ret;
	}
	}

	mutex_unlock(&outp->dp.hpd_irq_lock);

	nouveau_connector_hpd(nv_connector, NVIF_CONN_EVENT_V0_IRQ \| hpd);
	}

	/* TODO:
	* - Validate against the DP caps advertised by the GPU (we don't check these
	* yet)
	*/
	enum drm_mode_status
	nv50_dp_mode_valid(struct nouveau_encoder *outp,
	const struct drm_display_mode *mode,
	unsigned *out_clock)
	{
	const unsigned int min_clock = 25000;
	unsigned int max_rate, mode_rate, ds_max_dotclock, clock = mode->clock;
	/* Check with the minmum bpc always, so we can advertise better modes.
	* In particlar not doing this causes modes to be dropped on HDR
	* displays as we might check with a bpc of 16 even.
	*/
	const u8 bpp = 6 * 3;

	if (mode->flags & DRM_MODE_FLAG_INTERLACE && !outp->caps.dp_interlace)
	return MODE_NO_INTERLACE;

	if ((mode->flags & DRM_MODE_FLAG_3D_MASK) == DRM_MODE_FLAG_3D_FRAME_PACKING)
	clock *= 2;

	max_rate = outp->dp.link_nr * outp->dp.link_bw;
	mode_rate = DIV_ROUND_UP(clock * bpp, 8);
	if (mode_rate > max_rate)
	return MODE_CLOCK_HIGH;

	ds_max_dotclock = drm_dp_downstream_max_dotclock(outp->dp.dpcd, outp->dp.downstream_ports);
	if (ds_max_dotclock && clock > ds_max_dotclock)
	return MODE_CLOCK_HIGH;

	if (clock < min_clock)
	return MODE_CLOCK_LOW;

	if (out_clock)
	*out_clock = clock;

	return MODE_OK;
	}