text: // SPDX-License-Identifier: MIT
  /*
   * Copyright 2018 Noralf Trønnes
   * Copyright (c) 2006-2009 Red Hat Inc.
   * Copyright (c) 2006-2008 Intel Corporation
   *   Jesse Barnes <jesse.barnes@intel.com>
   * Copyright (c) 2007 Dave Airlie <airlied@linux.ie>
   */
  
  #include <linux/module.h>
  #include <linux/mutex.h>
  #include <linux/slab.h>
  
  #include <drm/drm_atomic.h>
  #include <drm/drm_client.h>
  #include <drm/drm_connector.h>
  #include <drm/drm_crtc.h>
  #include <drm/drm_device.h>
  #include <drm/drm_drv.h>
  #include <drm/drm_encoder.h>
  #include <drm/drm_print.h>
  
  #include "drm_crtc_internal.h"
  #include "drm_internal.h"
  
  #define DRM_CLIENT_MAX_CLONED_CONNECTORS	8
  
  struct drm_client_offset {
  	int x, y;
  };
  
  int drm_client_modeset_create(struct drm_client_dev *client)
  {
  	struct drm_device *dev = client->dev;
  	unsigned int num_crtc = dev->mode_config.num_crtc;
  	unsigned int max_connector_count = 1;
  	struct drm_mode_set *modeset;
  	struct drm_crtc *crtc;
  	unsigned int i = 0;
  
  	/* Add terminating zero entry to enable index less iteration */
  	client->modesets = kcalloc(num_crtc + 1, sizeof(*client->modesets), GFP_KERNEL);
  	if (!client->modesets)
  		return -ENOMEM;
  
  	mutex_init(&client->modeset_mutex);
  
  	drm_for_each_crtc(crtc, dev)
  		client->modesets[i++].crtc = crtc;
  
  	/* Cloning is only supported in the single crtc case. */
  	if (num_crtc == 1)
  		max_connector_count = DRM_CLIENT_MAX_CLONED_CONNECTORS;
  
  	for (modeset = client->modesets; modeset->crtc; modeset++) {
  		modeset->connectors = kcalloc(max_connector_count,
  					      sizeof(*modeset->connectors), GFP_KERNEL);
  		if (!modeset->connectors)
  			goto err_free;
  	}
  
  	return 0;
  
  err_free:
  	drm_client_modeset_free(client);
  
  	return -ENOMEM;
  }
  
  static void drm_client_modeset_release(struct drm_client_dev *client)
  {
  	struct drm_mode_set *modeset;
  	unsigned int i;
  
  	drm_client_for_each_modeset(modeset, client) {
  		drm_mode_destroy(client->dev, modeset->mode);
  		modeset->mode = NULL;
  		modeset->fb = NULL;
  
  		for (i = 0; i < modeset->num_connectors; i++) {
  			drm_connector_put(modeset->connectors[i]);
  			modeset->connectors[i] = NULL;
  		}
  		modeset->num_connectors = 0;
  	}
  }
  
  void drm_client_modeset_free(struct drm_client_dev *client)
  {
  	struct drm_mode_set *modeset;
  
  	mutex_lock(&client->modeset_mutex);
  
  	drm_client_modeset_release(client);
  
  	drm_client_for_each_modeset(modeset, client)
  		kfree(modeset->connectors);
  
  	mutex_unlock(&client->modeset_mutex);
  
  	mutex_destroy(&client->modeset_mutex);
  	kfree(client->modesets);
  }
  
  static struct drm_mode_set *
  drm_client_find_modeset(struct drm_client_dev *client, struct drm_crtc *crtc)
  {
  	struct drm_mode_set *modeset;
  
  	drm_client_for_each_modeset(modeset, client)
  		if (modeset->crtc == crtc)
  			return modeset;
  
  	return NULL;
  }
  
  static struct drm_display_mode *
  drm_connector_get_tiled_mode(struct drm_connector *connector)
  {
  	struct drm_display_mode *mode;
  
  	list_for_each_entry(mode, &connector->modes, head) {
  		if (mode->hdisplay == connector->tile_h_size &&
  		    mode->vdisplay == connector->tile_v_size)
  			return mode;
  	}
  	return NULL;
  }
  
  static struct drm_display_mode *
  drm_connector_fallback_non_tiled_mode(struct drm_connector *connector)
  {
  	struct drm_display_mode *mode;
  
  	list_for_each_entry(mode, &connector->modes, head) {
  		if (mode->hdisplay == connector->tile_h_size &&
  		    mode->vdisplay == connector->tile_v_size)
  			continue;
  		return mode;
  	}
  	return NULL;
  }
  
  static struct drm_display_mode *
  drm_connector_has_preferred_mode(struct drm_connector *connector, int width, int height)
  {
  	struct drm_display_mode *mode;
  
  	list_for_each_entry(mode, &connector->modes, head) {
  		if (mode->hdisplay > width ||
  		    mode->vdisplay > height)
  			continue;
  		if (mode->type & DRM_MODE_TYPE_PREFERRED)
  			return mode;
  	}
  	return NULL;
  }
  
  static struct drm_display_mode *
  drm_connector_pick_cmdline_mode(struct drm_connector *connector)
  {
  	struct drm_cmdline_mode *cmdline_mode;
  	struct drm_display_mode *mode;
  	bool prefer_non_interlace;
  
  	cmdline_mode = &connector->cmdline_mode;
  	if (cmdline_mode->specified == false)
  		return NULL;
  
  	/* attempt to find a matching mode in the list of modes
  	 *  we have gotten so far, if not add a CVT mode that conforms
  	 */
  	if (cmdline_mode->rb || cmdline_mode->margins)
  		goto create_mode;
  
  	prefer_non_interlace = !cmdline_mode->interlace;
  again:
  	list_for_each_entry(mode, &connector->modes, head) {
  		/* Check (optional) mode name first */
  		if (!strcmp(mode->name, cmdline_mode->name))
  			return mode;
  
  		/* check width/height */
  		if (mode->hdisplay != cmdline_mode->xres ||
  		    mode->vdisplay != cmdline_mode->yres)
  			continue;
  
  		if (cmdline_mode->refresh_specified) {
  			if (drm_mode_vrefresh(mode) != cmdline_mode->refresh)
  				continue;
  		}
  
  		if (cmdline_mode->interlace) {
  			if (!(mode->flags & DRM_MODE_FLAG_INTERLACE))
  				continue;
  		} else if (prefer_non_interlace) {
  			if (mode->flags & DRM_MODE_FLAG_INTERLACE)
  				continue;
  		}
  		return mode;
  	}
  
  	if (prefer_non_interlace) {
  		prefer_non_interlace = false;
  		goto again;
  	}
  
  create_mode:
  	mode = drm_mode_create_from_cmdline_mode(connector->dev, cmdline_mode);
  	if (mode)
  		list_add(&mode->head, &connector->modes);
  
  	return mode;
  }
  
  static bool drm_connector_enabled(struct drm_connector *connector, bool strict)
  {
  	bool enable;
  
  	if (connector->display_info.non_desktop)
  		return false;
  
  	if (strict)
  		enable = connector->status == connector_status_connected;
  	else
  		enable = connector->status != connector_status_disconnected;
  
  	return enable;
  }
  
  static void drm_client_connectors_enabled(struct drm_connector **connectors,
  					  unsigned int connector_count,
  					  bool *enabled)
  {
  	bool any_enabled = false;
  	struct drm_connector *connector;
  	int i = 0;
  
  	for (i = 0; i < connector_count; i++) {
  		connector = connectors[i];
  		enabled[i] = drm_connector_enabled(connector, true);
  		DRM_DEBUG_KMS("connector %d enabled? %s\n", connector->base.id,
  			      connector->display_info.non_desktop ? "non desktop" : enabled[i] ? "yes" : "no");
  
  		any_enabled |= enabled[i];
  	}
  
  	if (any_enabled)
  		return;
  
  	for (i = 0; i < connector_count; i++)
  		enabled[i] = drm_connector_enabled(connectors[i], false);
  }
  
  static bool drm_client_target_cloned(struct drm_device *dev,
  				     struct drm_connector **connectors,
  				     unsigned int connector_count,
  				     struct drm_display_mode **modes,
  				     struct drm_client_offset *offsets,
  				     bool *enabled, int width, int height)
  {
  	int count, i, j;
  	bool can_clone = false;
  	struct drm_display_mode *dmt_mode, *mode;
  
  	/* only contemplate cloning in the single crtc case */
  	if (dev->mode_config.num_crtc > 1)
  		return false;
  
  	count = 0;
  	for (i = 0; i < connector_count; i++) {
  		if (enabled[i])
  			count++;
  	}
  
  	/* only contemplate cloning if more than one connector is enabled */
  	if (count <= 1)
  		return false;
  
  	/* check the command line or if nothing common pick 1024x768 */
  	can_clone = true;
  	for (i = 0; i < connector_count; i++) {
  		if (!enabled[i])
  			continue;
  		modes[i] = drm_connector_pick_cmdline_mode(connectors[i]);
  		if (!modes[i]) {
  			can_clone = false;
  			break;
  		}
  		for (j = 0; j < i; j++) {
  			if (!enabled[j])
  				continue;
  			if (!drm_mode_match(modes[j], modes[i],
  					    DRM_MODE_MATCH_TIMINGS |
  					    DRM_MODE_MATCH_CLOCK |
  					    DRM_MODE_MATCH_FLAGS |
  					    DRM_MODE_MATCH_3D_FLAGS))
  				can_clone = false;
  		}
  	}
  
  	if (can_clone) {
  		DRM_DEBUG_KMS("can clone using command line\n");
  		return true;
  	}
  
  	/* try and find a 1024x768 mode on each connector */
  	can_clone = true;
  	dmt_mode = drm_mode_find_dmt(dev, 1024, 768, 60, false);
  
  	for (i = 0; i < connector_count; i++) {
  		if (!enabled[i])
  			continue;
  
  		list_for_each_entry(mode, &connectors[i]->modes, head) {
  			if (drm_mode_match(mode, dmt_mode,
  					   DRM_MODE_MATCH_TIMINGS |
  					   DRM_MODE_MATCH_CLOCK |
  					   DRM_MODE_MATCH_FLAGS |
  					   DRM_MODE_MATCH_3D_FLAGS))
  				modes[i] = mode;
  		}
  		if (!modes[i])
  			can_clone = false;
  	}
  
  	if (can_clone) {
  		DRM_DEBUG_KMS("can clone using 1024x768\n");
  		return true;
  	}
  	DRM_INFO("kms: can't enable cloning when we probably wanted to.\n");
  	return false;
  }
  
  static int drm_client_get_tile_offsets(struct drm_connector **connectors,
  				       unsigned int connector_count,
  				       struct drm_display_mode **modes,
  				       struct drm_client_offset *offsets,
  				       int idx,
  				       int h_idx, int v_idx)
  {
  	struct drm_connector *connector;
  	int i;
  	int hoffset = 0, voffset = 0;
  
  	for (i = 0; i < connector_count; i++) {
  		connector = connectors[i];
  		if (!connector->has_tile)
  			continue;
  
  		if (!modes[i] && (h_idx || v_idx)) {
  			DRM_DEBUG_KMS("no modes for connector tiled %d %d\n", i,
  				      connector->base.id);
  			continue;
  		}
  		if (connector->tile_h_loc < h_idx)
  			hoffset += modes[i]->hdisplay;
  
  		if (connector->tile_v_loc < v_idx)
  			voffset += modes[i]->vdisplay;
  	}
  	offsets[idx].x = hoffset;
  	offsets[idx].y = voffset;
  	DRM_DEBUG_KMS("returned %d %d for %d %d\n", hoffset, voffset, h_idx, v_idx);
  	return 0;
  }
  
  static bool drm_client_target_preferred(struct drm_connector **connectors,
  					unsigned int connector_count,
  					struct drm_display_mode **modes,
  					struct drm_client_offset *offsets,
  					bool *enabled, int width, int height)
  {
  	const u64 mask = BIT_ULL(connector_count) - 1;
  	struct drm_connector *connector;
  	u64 conn_configured = 0;
  	int tile_pass = 0;
  	int num_tiled_conns = 0;
  	int i;
  
  	for (i = 0; i < connector_count; i++) {
  		if (connectors[i]->has_tile &&
  		    connectors[i]->status == connector_status_connected)
  			num_tiled_conns++;
  	}
  
  retry:
  	for (i = 0; i < connector_count; i++) {
  		connector = connectors[i];
  
  		if (conn_configured & BIT_ULL(i))
  			continue;
  
  		if (enabled[i] == false) {
  			conn_configured |= BIT_ULL(i);
  			continue;
  		}
  
  		/* first pass over all the untiled connectors */
  		if (tile_pass == 0 && connector->has_tile)
  			continue;
  
  		if (tile_pass == 1) {
  			if (connector->tile_h_loc != 0 ||
  			    connector->tile_v_loc != 0)
  				continue;
  
  		} else {
  			if (connector->tile_h_loc != tile_pass - 1 &&
  			    connector->tile_v_loc != tile_pass - 1)
  			/* if this tile_pass doesn't cover any of the tiles - keep going */
  				continue;
  
  			/*
  			 * find the tile offsets for this pass - need to find
  			 * all tiles left and above
  			 */
  			drm_client_get_tile_offsets(connectors, connector_count, modes, offsets, i,
  						    connector->tile_h_loc, connector->tile_v_loc);
  		}
  		DRM_DEBUG_KMS("looking for cmdline mode on connector %d\n",
  			      connector->base.id);
  
  		/* got for command line mode first */
  		modes[i] = drm_connector_pick_cmdline_mode(connector);
  		if (!modes[i]) {
  			DRM_DEBUG_KMS("looking for preferred mode on connector %d %d\n",
  				      connector->base.id, connector->tile_group ? connector->tile_group->id : 0);
  			modes[i] = drm_connector_has_preferred_mode(connector, width, height);
  		}
  		/* No preferred modes, pick one off the list */
  		if (!modes[i] && !list_empty(&connector->modes)) {
  			list_for_each_entry(modes[i], &connector->modes, head)
  				break;
  		}
  		/*
  		 * In case of tiled mode if all tiles not present fallback to
  		 * first available non tiled mode.
  		 * After all tiles are present, try to find the tiled mode
  		 * for all and if tiled mode not present due to fbcon size
  		 * limitations, use first non tiled mode only for
  		 * tile 0,0 and set to no mode for all other tiles.
  		 */
  		if (connector->has_tile) {
  			if (num_tiled_conns <
  			    connector->num_h_tile * connector->num_v_tile ||
  			    (connector->tile_h_loc == 0 &&
  			     connector->tile_v_loc == 0 &&
  			     !drm_connector_get_tiled_mode(connector))) {
  				DRM_DEBUG_KMS("Falling back to non tiled mode on Connector %d\n",
  					      connector->base.id);
  				modes[i] = drm_connector_fallback_non_tiled_mode(connector);
  			} else {
  				modes[i] = drm_connector_get_tiled_mode(connector);
  			}
  		}
  
  		DRM_DEBUG_KMS("found mode %s\n", modes[i] ? modes[i]->name :
  			  "none");
  		conn_configured |= BIT_ULL(i);
  	}
  
  	if ((conn_configured & mask) != mask) {
  		tile_pass++;
  		goto retry;
  	}
  	return true;
  }
  
  static bool connector_has_possible_crtc(struct drm_connector *connector,
  					struct drm_crtc *crtc)
  {
  	struct drm_encoder *encoder;
  
  	drm_connector_for_each_possible_encoder(connector, encoder) {
  		if (encoder->possible_crtcs & drm_crtc_mask(crtc))
  			return true;
  	}
  
  	return false;
  }
  
  static int drm_client_pick_crtcs(struct drm_client_dev *client,
  				 struct drm_connector **connectors,
  				 unsigned int connector_count,
  				 struct drm_crtc **best_crtcs,
  				 struct drm_display_mode **modes,
  				 int n, int width, int height)
  {
  	struct drm_device *dev = client->dev;
  	struct drm_connector *connector;
  	int my_score, best_score, score;
  	struct drm_crtc **crtcs, *crtc;
  	struct drm_mode_set *modeset;
  	int o;
  
  	if (n == connector_count)
  		return 0;
  
  	connector = connectors[n];
  
  	best_crtcs[n] = NULL;
  	best_score = drm_client_pick_crtcs(client, connectors, connector_count,
  					   best_crtcs, modes, n + 1, width, height);
  	if (modes[n] == NULL)
  		return best_score;
  
  	crtcs = kcalloc(connector_count, sizeof(*crtcs), GFP_KERNEL);
  	if (!crtcs)
  		return best_score;
  
  	my_score = 1;
  	if (connector->status == connector_status_connected)
  		my_score++;
  	if (connector->cmdline_mode.specified)
  		my_score++;
  	if (drm_connector_has_preferred_mode(connector, width, height))
  		my_score++;
  
  	/*
  	 * select a crtc for this connector and then attempt to configure
  	 * remaining connectors
  	 */
  	drm_client_for_each_modeset(modeset, client) {
  		crtc = modeset->crtc;
  
  		if (!connector_has_possible_crtc(connector, crtc))
  			continue;
  
  		for (o = 0; o < n; o++)
  			if (best_crtcs[o] == crtc)
  				break;
  
  		if (o < n) {
  			/* ignore cloning unless only a single crtc */
  			if (dev->mode_config.num_crtc > 1)
  				continue;
  
  			if (!drm_mode_equal(modes[o], modes[n]))
  				continue;
  		}
  
  		crtcs[n] = crtc;
  		memcpy(crtcs, best_crtcs, n * sizeof(*crtcs));
  		score = my_score + drm_client_pick_crtcs(client, connectors, connector_count,
  							 crtcs, modes, n + 1, width, height);
  		if (score > best_score) {
  			best_score = score;
  			memcpy(best_crtcs, crtcs, connector_count * sizeof(*crtcs));
  		}
  	}
  
  	kfree(crtcs);
  	return best_score;
  }
  
  /* Try to read the BIOS display configuration and use it for the initial config */
  static bool drm_client_firmware_config(struct drm_client_dev *client,
  				       struct drm_connector **connectors,
  				       unsigned int connector_count,
  				       struct drm_crtc **crtcs,
  				       struct drm_display_mode **modes,
  				       struct drm_client_offset *offsets,
  				       bool *enabled, int width, int height)
  {
  	const int count = min_t(unsigned int, connector_count, BITS_PER_LONG);
  	unsigned long conn_configured, conn_seq, mask;
  	struct drm_device *dev = client->dev;
  	int i, j;
  	bool *save_enabled;
  	bool fallback = true, ret = true;
  	int num_connectors_enabled = 0;
  	int num_connectors_detected = 0;
  	int num_tiled_conns = 0;
  	struct drm_modeset_acquire_ctx ctx;
  
  	if (!drm_drv_uses_atomic_modeset(dev))
  		return false;
  
  	if (WARN_ON(count <= 0))
  		return false;
  
  	save_enabled = kcalloc(count, sizeof(bool), GFP_KERNEL);
  	if (!save_enabled)
  		return false;
  
  	drm_modeset_acquire_init(&ctx, 0);
  
  	while (drm_modeset_lock_all_ctx(dev, &ctx) != 0)
  		drm_modeset_backoff(&ctx);
  
  	memcpy(save_enabled, enabled, count);
  	mask = GENMASK(count - 1, 0);
  	conn_configured = 0;
  	for (i = 0; i < count; i++) {
  		if (connectors[i]->has_tile &&
  		    connectors[i]->status == connector_status_connected)
  			num_tiled_conns++;
  	}
  retry:
  	conn_seq = conn_configured;
  	for (i = 0; i < count; i++) {
  		struct drm_connector *connector;
  		struct drm_encoder *encoder;
  		struct drm_crtc *new_crtc;
  
  		connector = connectors[i];
  
  		if (conn_configured & BIT(i))
  			continue;
  
  		if (conn_seq == 0 && !connector->has_tile)
  			continue;
  
  		if (connector->status == connector_status_connected)
  			num_connectors_detected++;
  
  		if (!enabled[i]) {
  			DRM_DEBUG_KMS("connector %s not enabled, skipping\n",
  				      connector->name);
  			conn_configured |= BIT(i);
  			continue;
  		}
  
  		if (connector->force == DRM_FORCE_OFF) {
  			DRM_DEBUG_KMS("connector %s is disabled by user, skipping\n",
  				      connector->name);
  			enabled[i] = false;
  			continue;
  		}
  
  		encoder = connector->state->best_encoder;
  		if (!encoder || WARN_ON(!connector->state->crtc)) {
  			if (connector->force > DRM_FORCE_OFF)
  				goto bail;
  
  			DRM_DEBUG_KMS("connector %s has no encoder or crtc, skipping\n",
  				      connector->name);
  			enabled[i] = false;
  			conn_configured |= BIT(i);
  			continue;
  		}
  
  		num_connectors_enabled++;
  
  		new_crtc = connector->state->crtc;
  
  		/*
  		 * Make sure we're not trying to drive multiple connectors
  		 * with a single CRTC, since our cloning support may not
  		 * match the BIOS.
  		 */
  		for (j = 0; j < count; j++) {
  			if (crtcs[j] == new_crtc) {
  				DRM_DEBUG_KMS("fallback: cloned configuration\n");
  				goto bail;
  			}
  		}
  
  		DRM_DEBUG_KMS("looking for cmdline mode on connector %s\n",
  			      connector->name);
  
  		/* go for command line mode first */
  		modes[i] = drm_connector_pick_cmdline_mode(connector);
  
  		/* try for preferred next */
  		if (!modes[i]) {
  			DRM_DEBUG_KMS("looking for preferred mode on connector %s %d\n",
  				      connector->name, connector->has_tile);
  			modes[i] = drm_connector_has_preferred_mode(connector, width, height);
  		}
  
  		/* No preferred mode marked by the EDID? Are there any modes? */
  		if (!modes[i] && !list_empty(&connector->modes)) {
  			DRM_DEBUG_KMS("using first mode listed on connector %s\n",
  				      connector->name);
  			modes[i] = list_first_entry(&connector->modes,
  						    struct drm_display_mode,
  						    head);
  		}
  
  		/* last resort: use current mode */
  		if (!modes[i]) {
  			/*
  			 * IMPORTANT: We want to use the adjusted mode (i.e.
  			 * after the panel fitter upscaling) as the initial
  			 * config, not the input mode, which is what crtc->mode
  			 * usually contains. But since our current
  			 * code puts a mode derived from the post-pfit timings
  			 * into crtc->mode this works out correctly.
  			 *
  			 * This is crtc->mode and not crtc->state->mode for the
  			 * fastboot check to work correctly.
  			 */
  			DRM_DEBUG_KMS("looking for current mode on connector %s\n",
  				      connector->name);
  			modes[i] = &connector->state->crtc->mode;
  		}
  		/*
  		 * In case of tiled modes, if all tiles are not present
  		 * then fallback to a non tiled mode.
  		 */
  		if (connector->has_tile &&
  		    num_tiled_conns < connector->num_h_tile * connector->num_v_tile) {
  			DRM_DEBUG_KMS("Falling back to non tiled mode on Connector %d\n",
  				      connector->base.id);
  			modes[i] = drm_connector_fallback_non_tiled_mode(connector);
  		}
  		crtcs[i] = new_crtc;
  
  		DRM_DEBUG_KMS("connector %s on [CRTC:%d:%s]: %dx%d%s\n",
  			      connector->name,
  			      connector->state->crtc->base.id,
  			      connector->state->crtc->name,
  			      modes[i]->hdisplay, modes[i]->vdisplay,
  			      modes[i]->flags & DRM_MODE_FLAG_INTERLACE ? "i" : "");
  
  		fallback = false;
  		conn_configured |= BIT(i);
  	}
  
  	if ((conn_configured & mask) != mask && conn_configured != conn_seq)
  		goto retry;
  
  	/*
  	 * If the BIOS didn't enable everything it could, fall back to have the
  	 * same user experiencing of lighting up as much as possible like the
  	 * fbdev helper library.
  	 */
  	if (num_connectors_enabled != num_connectors_detected &&
  	    num_connectors_enabled < dev->mode_config.num_crtc) {
  		DRM_DEBUG_KMS("fallback: Not all outputs enabled\n");
  		DRM_DEBUG_KMS("Enabled: %i, detected: %i\n", num_connectors_enabled,
  			      num_connectors_detected);
  		fallback = true;
  	}
  
  	if (fallback) {
  bail:
  		DRM_DEBUG_KMS("Not using firmware configuration\n");
  		memcpy(enabled, save_enabled, count);
  		ret = false;
  	}
  
  	drm_modeset_drop_locks(&ctx);
  	drm_modeset_acquire_fini(&ctx);
  
  	kfree(save_enabled);
  	return ret;
  }
  
  /**
   * drm_client_modeset_probe() - Probe for displays
   * @client: DRM client
   * @width: Maximum display mode width (optional)
   * @height: Maximum display mode height (optional)
   *
   * This function sets up display pipelines for enabled connectors and stores the
   * config in the client's modeset array.
   *
   * Returns:
   * Zero on success or negative error code on failure.
   */
  int drm_client_modeset_probe(struct drm_client_dev *client, unsigned int width, unsigned int height)
  {
  	struct drm_connector *connector, **connectors = NULL;
  	struct drm_connector_list_iter conn_iter;
  	struct drm_device *dev = client->dev;
  	unsigned int total_modes_count = 0;
  	struct drm_client_offset *offsets;
  	unsigned int connector_count = 0;
  	struct drm_display_mode **modes;
  	struct drm_crtc **crtcs;
  	int i, ret = 0;
  	bool *enabled;
  
  	DRM_DEBUG_KMS("\n");
  
  	if (!width)
  		width = dev->mode_config.max_width;
  	if (!height)
  		height = dev->mode_config.max_height;
  
  	drm_connector_list_iter_begin(dev, &conn_iter);
  	drm_client_for_each_connector_iter(connector, &conn_iter) {
  		struct drm_connector **tmp;
  
  		tmp = krealloc(connectors, (connector_count + 1) * sizeof(*connectors), GFP_KERNEL);
  		if (!tmp) {
  			ret = -ENOMEM;
  			goto free_connectors;
  		}
  
  		connectors = tmp;
  		drm_connector_get(connector);
  		connectors[connector_count++] = connector;
  	}
  	drm_connector_list_iter_end(&conn_iter);
  
  	if (!connector_count)
  		return 0;
  
  	crtcs = kcalloc(connector_count, sizeof(*crtcs), GFP_KERNEL);
  	modes = kcalloc(connector_count, sizeof(*modes), GFP_KERNEL);
  	offsets = kcalloc(connector_count, sizeof(*offsets), GFP_KERNEL);
  	enabled = kcalloc(connector_count, sizeof(bool), GFP_KERNEL);
  	if (!crtcs || !modes || !enabled || !offsets) {
  		DRM_ERROR("Memory allocation failed\n");
  		ret = -ENOMEM;
  		goto out;
  	}
  
  	mutex_lock(&client->modeset_mutex);
  
  	mutex_lock(&dev->mode_config.mutex);
  	for (i = 0; i < connector_count; i++)
  		total_modes_count += connectors[i]->funcs->fill_modes(connectors[i], width, height);
  	if (!total_modes_count)
  		DRM_DEBUG_KMS("No connectors reported connected with modes\n");
  	drm_client_connectors_enabled(connectors, connector_count, enabled);
  
  	if (!drm_client_firmware_config(client, connectors, connector_count, crtcs,
  					modes, offsets, enabled, width, height)) {
  		memset(modes, 0, connector_count * sizeof(*modes));
  		memset(crtcs, 0, connector_count * sizeof(*crtcs));
  		memset(offsets, 0, connector_count * sizeof(*offsets));
  
  		if (!drm_client_target_cloned(dev, connectors, connector_count, modes,
  					      offsets, enabled, width, height) &&
  		    !drm_client_target_preferred(connectors, connector_count, modes,
  						 offsets, enabled, width, height))
  			DRM_ERROR("Unable to find initial modes\n");
  
  		DRM_DEBUG_KMS("picking CRTCs for %dx%d config\n",
  			      width, height);
  
  		drm_client_pick_crtcs(client, connectors, connector_count,
  				      crtcs, modes, 0, width, height);
  	}
  	mutex_unlock(&dev->mode_config.mutex);
  
  	drm_client_modeset_release(client);
  
  	for (i = 0; i < connector_count; i++) {
  		struct drm_display_mode *mode = modes[i];
  		struct drm_crtc *crtc = crtcs[i];
  		struct drm_client_offset *offset = &offsets[i];
  
  		if (mode && crtc) {
  			struct drm_mode_set *modeset = drm_client_find_modeset(client, crtc);
  			struct drm_connector *connector = connectors[i];
  
  			DRM_DEBUG_KMS("desired mode %s set on crtc %d (%d,%d)\n",
  				      mode->name, crtc->base.id, offset->x, offset->y);
  
  			if (WARN_ON_ONCE(modeset->num_connectors == DRM_CLIENT_MAX_CLONED_CONNECTORS ||
  					 (dev->mode_config.num_crtc > 1 && modeset->num_connectors == 1))) {
  				ret = -EINVAL;
  				break;
  			}
  
  			modeset->mode = drm_mode_duplicate(dev, mode);
  			drm_connector_get(connector);
  			modeset->connectors[modeset->num_connectors++] = connector;
  			modeset->x = offset->x;
  			modeset->y = offset->y;
  		}
  	}
  
  	mutex_unlock(&client->modeset_mutex);
  out:
  	kfree(crtcs);
  	kfree(modes);
  	kfree(offsets);
  	kfree(enabled);
  free_connectors:
  	for (i = 0; i < connector_count; i++)
  		drm_connector_put(connectors[i]);
  	kfree(connectors);
  
  	return ret;
  }
  EXPORT_SYMBOL(drm_client_modeset_probe);
  
  /**
   * drm_client_rotation() - Check the initial rotation value
   * @modeset: DRM modeset
   * @rotation: Returned rotation value
   *
   * This function checks if the primary plane in @modeset can hw rotate
   * to match the rotation needed on its connector.
   *
   * Note: Currently only 0 and 180 degrees are supported.
   *
   * Return:
   * True if the plane can do the rotation, false otherwise.
   */
  bool drm_client_rotation(struct drm_mode_set *modeset, unsigned int *rotation)
  {
  	struct drm_connector *connector = modeset->connectors[0];
  	struct drm_plane *plane = modeset->crtc->primary;
  	struct drm_cmdline_mode *cmdline;
  	u64 valid_mask = 0;
  	unsigned int i;
  
  	if (!modeset->num_connectors)
  		return false;
  
  	switch (connector->display_info.panel_orientation) {
  	case DRM_MODE_PANEL_ORIENTATION_BOTTOM_UP:
  		*rotation = DRM_MODE_ROTATE_180;
  		break;
  	case DRM_MODE_PANEL_ORIENTATION_LEFT_UP:
  		*rotation = DRM_MODE_ROTATE_90;
  		break;
  	case DRM_MODE_PANEL_ORIENTATION_RIGHT_UP:
  		*rotation = DRM_MODE_ROTATE_270;
  		break;
  	default:
  		*rotation = DRM_MODE_ROTATE_0;
  	}
  
  	/**
  	 * The panel already defined the default rotation
  	 * through its orientation. Whatever has been provided
  	 * on the command line needs to be added to that.
  	 *
  	 * Unfortunately, the rotations are at different bit
  	 * indices, so the math to add them up are not as
  	 * trivial as they could.
  	 *
  	 * Reflections on the other hand are pretty trivial to deal with, a
  	 * simple XOR between the two handle the addition nicely.
  	 */
  	cmdline = &connector->cmdline_mode;
  	if (cmdline->specified && cmdline->rotation_reflection) {
  		unsigned int cmdline_rest, panel_rest;
  		unsigned int cmdline_rot, panel_rot;
  		unsigned int sum_rot, sum_rest;
  
  		panel_rot = ilog2(*rotation & DRM_MODE_ROTATE_MASK);
  		cmdline_rot = ilog2(cmdline->rotation_reflection & DRM_MODE_ROTATE_MASK);
  		sum_rot = (panel_rot + cmdline_rot) % 4;
  
  		panel_rest = *rotation & ~DRM_MODE_ROTATE_MASK;
  		cmdline_rest = cmdline->rotation_reflection & ~DRM_MODE_ROTATE_MASK;
  		sum_rest = panel_rest ^ cmdline_rest;
  
  		*rotation = (1 << sum_rot) | sum_rest;
  	}
  
  	/*
  	 * TODO: support 90 / 270 degree hardware rotation,
  	 * depending on the hardware this may require the framebuffer
  	 * to be in a specific tiling format.
  	 */
  	if (((*rotation & DRM_MODE_ROTATE_MASK) != DRM_MODE_ROTATE_0 &&
  	     (*rotation & DRM_MODE_ROTATE_MASK) != DRM_MODE_ROTATE_180) ||
  	    !plane->rotation_property)
  		return false;
  
  	for (i = 0; i < plane->rotation_property->num_values; i++)
  		valid_mask |= (1ULL << plane->rotation_property->values[i]);
  
  	if (!(*rotation & valid_mask))
  		return false;
  
  	return true;
  }
  EXPORT_SYMBOL(drm_client_rotation);
  
  static int drm_client_modeset_commit_atomic(struct drm_client_dev *client, bool active, bool check)
  {
  	struct drm_device *dev = client->dev;
  	struct drm_plane *plane;
  	struct drm_atomic_state *state;
  	struct drm_modeset_acquire_ctx ctx;
  	struct drm_mode_set *mode_set;
  	int ret;
  
  	drm_modeset_acquire_init(&ctx, 0);
  
  	state = drm_atomic_state_alloc(dev);
  	if (!state) {
  		ret = -ENOMEM;
  		goto out_ctx;
  	}
  
  	state->acquire_ctx = &ctx;
  retry:
  	drm_for_each_plane(plane, dev) {
  		struct drm_plane_state *plane_state;
  
  		plane_state = drm_atomic_get_plane_state(state, plane);
  		if (IS_ERR(plane_state)) {
  			ret = PTR_ERR(plane_state);
  			goto out_state;
  		}
  
  		plane_state->rotation = DRM_MODE_ROTATE_0;
  
  		/* disable non-primary: */
  		if (plane->type == DRM_PLANE_TYPE_PRIMARY)
  			continue;
  
  		ret = __drm_atomic_helper_disable_plane(plane, plane_state);
  		if (ret != 0)
  			goto out_state;
  	}
  
  	drm_client_for_each_modeset(mode_set, client) {
  		struct drm_plane *primary = mode_set->crtc->primary;
  		unsigned int rotation;
  
  		if (drm_client_rotation(mode_set, &rotation)) {
  			struct drm_plane_state *plane_state;
  
  			/* Cannot fail as we've already gotten the plane state above */
  			plane_state = drm_atomic_get_new_plane_state(state, primary);
  			plane_state->rotation = rotation;
  		}
  
  		ret = __drm_atomic_helper_set_config(mode_set, state);
  		if (ret != 0)
  			goto out_state;
  
  		/*
  		 * __drm_atomic_helper_set_config() sets active when a
  		 * mode is set, unconditionally clear it if we force DPMS off
  		 */
  		if (!active) {
  			struct drm_crtc *crtc = mode_set->crtc;
  			struct drm_crtc_state *crtc_state = drm_atomic_get_new_crtc_state(state, crtc);
  
  			crtc_state->active = false;
  		}
  	}
  
  	if (check)
  		ret = drm_atomic_check_only(state);
  	else
  		ret = drm_atomic_commit(state);
  
  out_state:
  	if (ret == -EDEADLK)
  		goto backoff;
  
  	drm_atomic_state_put(state);
  out_ctx:
  	drm_modeset_drop_locks(&ctx);
  	drm_modeset_acquire_fini(&ctx);
  
  	return ret;
  
  backoff:
  	drm_atomic_state_clear(state);
  	drm_modeset_backoff(&ctx);
  
  	goto retry;
  }
  
  static int drm_client_modeset_commit_legacy(struct drm_client_dev *client)
  {
  	struct drm_device *dev = client->dev;
  	struct drm_mode_set *mode_set;
  	struct drm_plane *plane;
  	int ret = 0;
  
  	drm_modeset_lock_all(dev);
  	drm_for_each_plane(plane, dev) {
  		if (plane->type != DRM_PLANE_TYPE_PRIMARY)
  			drm_plane_force_disable(plane);
  
  		if (plane->rotation_property)
  			drm_mode_plane_set_obj_prop(plane,
  						    plane->rotation_property,
  						    DRM_MODE_ROTATE_0);
  	}
  
  	drm_client_for_each_modeset(mode_set, client) {
  		struct drm_crtc *crtc = mode_set->crtc;
  
  		if (crtc->funcs->cursor_set2) {
  			ret = crtc->funcs->cursor_set2(crtc, NULL, 0, 0, 0, 0, 0);
  			if (ret)
  				goto out;
  		} else if (crtc->funcs->cursor_set) {
  			ret = crtc->funcs->cursor_set(crtc, NULL, 0, 0, 0);
  			if (ret)
  				goto out;
  		}
  
  		ret = drm_mode_set_config_internal(mode_set);
  		if (ret)
  			goto out;
  	}
  out:
  	drm_modeset_unlock_all(dev);
  
  	return ret;
  }
  
  /**
   * drm_client_modeset_check() - Check modeset configuration
   * @client: DRM client
   *
   * Check modeset configuration.
   *
   * Returns:
   * Zero on success or negative error code on failure.
   */
  int drm_client_modeset_check(struct drm_client_dev *client)
  {
  	int ret;
  
  	if (!drm_drv_uses_atomic_modeset(client->dev))
  		return 0;
  
  	mutex_lock(&client->modeset_mutex);
  	ret = drm_client_modeset_commit_atomic(client, true, true);
  	mutex_unlock(&client->modeset_mutex);
  
  	return ret;
  }
  EXPORT_SYMBOL(drm_client_modeset_check);
  
  /**
   * drm_client_modeset_commit_locked() - Force commit CRTC configuration
   * @client: DRM client
   *
   * Commit modeset configuration to crtcs without checking if there is a DRM
   * master. The assumption is that the caller already holds an internal DRM
   * master reference acquired with drm_master_internal_acquire().
   *
   * Returns:
   * Zero on success or negative error code on failure.
   */
  int drm_client_modeset_commit_locked(struct drm_client_dev *client)
  {
  	struct drm_device *dev = client->dev;
  	int ret;
  
  	mutex_lock(&client->modeset_mutex);
  	if (drm_drv_uses_atomic_modeset(dev))
  		ret = drm_client_modeset_commit_atomic(client, true, false);
  	else
  		ret = drm_client_modeset_commit_legacy(client);
  	mutex_unlock(&client->modeset_mutex);
  
  	return ret;
  }
  EXPORT_SYMBOL(drm_client_modeset_commit_locked);
  
  /**
   * drm_client_modeset_commit() - Commit CRTC configuration
   * @client: DRM client
   *
   * Commit modeset configuration to crtcs.
   *
   * Returns:
   * Zero on success or negative error code on failure.
   */
  int drm_client_modeset_commit(struct drm_client_dev *client)
  {
  	struct drm_device *dev = client->dev;
  	int ret;
  
  	if (!drm_master_internal_acquire(dev))
  		return -EBUSY;
  
  	ret = drm_client_modeset_commit_locked(client);
  
  	drm_master_internal_release(dev);
  
  	return ret;
  }
  EXPORT_SYMBOL(drm_client_modeset_commit);
  
  static void drm_client_modeset_dpms_legacy(struct drm_client_dev *client, int dpms_mode)
  {
  	struct drm_device *dev = client->dev;
  	struct drm_connector *connector;
  	struct drm_mode_set *modeset;
  	int j;
  
  	drm_modeset_lock_all(dev);
  	drm_client_for_each_modeset(modeset, client) {
  		if (!modeset->crtc->enabled)
  			continue;
  
  		for (j = 0; j < modeset->num_connectors; j++) {
  			connector = modeset->connectors[j];
  			connector->funcs->dpms(connector, dpms_mode);
  			drm_object_property_set_value(&connector->base,
  				dev->mode_config.dpms_property, dpms_mode);
  		}
  	}
  	drm_modeset_unlock_all(dev);
  }
  
  /**
   * drm_client_modeset_dpms() - Set DPMS mode
   * @client: DRM client
   * @mode: DPMS mode
   *
   * Note: For atomic drivers @mode is reduced to on/off.
   *
   * Returns:
   * Zero on success or negative error code on failure.
   */
  int drm_client_modeset_dpms(struct drm_client_dev *client, int mode)
  {
  	struct drm_device *dev = client->dev;
  	int ret = 0;
  
  	if (!drm_master_internal_acquire(dev))
  		return -EBUSY;
  
  	mutex_lock(&client->modeset_mutex);
  	if (drm_drv_uses_atomic_modeset(dev))
  		ret = drm_client_modeset_commit_atomic(client, mode == DRM_MODE_DPMS_ON, false);
  	else
  		drm_client_modeset_dpms_legacy(client, mode);
  	mutex_unlock(&client->modeset_mutex);
  
  	drm_master_internal_release(dev);
  
  	return ret;
  }
  EXPORT_SYMBOL(drm_client_modeset_dpms);
  