Adding upstream version 6.1.76.upstream/6.1.76upstream

Signed-off-by: Daniel Baumann <daniel.baumann@progress-linux.org>

1 files changed, 1035 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_crtc_helper.c b/drivers/gpu/drm/drm_crtc_helper.c
new file mode 100644
index 000000000..7d86020b5
--- /dev/null
+++ b/drivers/gpu/drm/drm_crtc_helper.c
@@ -0,0 +1,1035 @@
+/*
+ * Copyright (c) 2006-2008 Intel Corporation
+ * Copyright (c) 2007 Dave Airlie <airlied@linux.ie>
+ *
+ * DRM core CRTC related functions
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and its
+ * documentation for any purpose is hereby granted without fee, provided that
+ * the above copyright notice appear in all copies and that both that copyright
+ * notice and this permission notice appear in supporting documentation, and
+ * that the name of the copyright holders not be used in advertising or
+ * publicity pertaining to distribution of the software without specific,
+ * written prior permission.  The copyright holders make no representations
+ * about the suitability of this software for any purpose.  It is provided "as
+ * is" without express or implied warranty.
+ *
+ * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
+ * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
+ * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+ * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
+ * OF THIS SOFTWARE.
+ *
+ * Authors:
+ *      Keith Packard
+ *	Eric Anholt <eric@anholt.net>
+ *      Dave Airlie <airlied@linux.ie>
+ *      Jesse Barnes <jesse.barnes@intel.com>
+ */
+
+#include <linux/export.h>
+#include <linux/kernel.h>
+#include <linux/moduleparam.h>
+#include <linux/dynamic_debug.h>
+
+#include <drm/drm_atomic.h>
+#include <drm/drm_atomic_helper.h>
+#include <drm/drm_atomic_uapi.h>
+#include <drm/drm_bridge.h>
+#include <drm/drm_crtc.h>
+#include <drm/drm_crtc_helper.h>
+#include <drm/drm_drv.h>
+#include <drm/drm_edid.h>
+#include <drm/drm_encoder.h>
+#include <drm/drm_fb_helper.h>
+#include <drm/drm_fourcc.h>
+#include <drm/drm_framebuffer.h>
+#include <drm/drm_print.h>
+#include <drm/drm_vblank.h>
+
+#include "drm_crtc_helper_internal.h"
+
+DECLARE_DYNDBG_CLASSMAP(drm_debug_classes, DD_CLASS_TYPE_DISJOINT_BITS, 0,
+			"DRM_UT_CORE",
+			"DRM_UT_DRIVER",
+			"DRM_UT_KMS",
+			"DRM_UT_PRIME",
+			"DRM_UT_ATOMIC",
+			"DRM_UT_VBL",
+			"DRM_UT_STATE",
+			"DRM_UT_LEASE",
+			"DRM_UT_DP",
+			"DRM_UT_DRMRES");
+
+/**
+ * DOC: overview
+ *
+ * The CRTC modeset helper library provides a default set_config implementation
+ * in drm_crtc_helper_set_config(). Plus a few other convenience functions using
+ * the same callbacks which drivers can use to e.g. restore the modeset
+ * configuration on resume with drm_helper_resume_force_mode().
+ *
+ * Note that this helper library doesn't track the current power state of CRTCs
+ * and encoders. It can call callbacks like &drm_encoder_helper_funcs.dpms even
+ * though the hardware is already in the desired state. This deficiency has been
+ * fixed in the atomic helpers.
+ *
+ * The driver callbacks are mostly compatible with the atomic modeset helpers,
+ * except for the handling of the primary plane: Atomic helpers require that the
+ * primary plane is implemented as a real standalone plane and not directly tied
+ * to the CRTC state. For easier transition this library provides functions to
+ * implement the old semantics required by the CRTC helpers using the new plane
+ * and atomic helper callbacks.
+ *
+ * Drivers are strongly urged to convert to the atomic helpers (by way of first
+ * converting to the plane helpers). New drivers must not use these functions
+ * but need to implement the atomic interface instead, potentially using the
+ * atomic helpers for that.
+ *
+ * These legacy modeset helpers use the same function table structures as
+ * all other modesetting helpers. See the documentation for struct
+ * &drm_crtc_helper_funcs, &struct drm_encoder_helper_funcs and struct
+ * &drm_connector_helper_funcs.
+ */
+
+/**
+ * drm_helper_encoder_in_use - check if a given encoder is in use
+ * @encoder: encoder to check
+ *
+ * Checks whether @encoder is with the current mode setting output configuration
+ * in use by any connector. This doesn't mean that it is actually enabled since
+ * the DPMS state is tracked separately.
+ *
+ * Returns:
+ * True if @encoder is used, false otherwise.
+ */
+bool drm_helper_encoder_in_use(struct drm_encoder *encoder)
+{
+	struct drm_connector *connector;
+	struct drm_connector_list_iter conn_iter;
+	struct drm_device *dev = encoder->dev;
+
+	WARN_ON(drm_drv_uses_atomic_modeset(dev));
+
+	/*
+	 * We can expect this mutex to be locked if we are not panicking.
+	 * Locking is currently fubar in the panic handler.
+	 */
+	if (!oops_in_progress) {
+		WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
+		WARN_ON(!drm_modeset_is_locked(&dev->mode_config.connection_mutex));
+	}
+
+
+	drm_connector_list_iter_begin(dev, &conn_iter);
+	drm_for_each_connector_iter(connector, &conn_iter) {
+		if (connector->encoder == encoder) {
+			drm_connector_list_iter_end(&conn_iter);
+			return true;
+		}
+	}
+	drm_connector_list_iter_end(&conn_iter);
+	return false;
+}
+EXPORT_SYMBOL(drm_helper_encoder_in_use);
+
+/**
+ * drm_helper_crtc_in_use - check if a given CRTC is in a mode_config
+ * @crtc: CRTC to check
+ *
+ * Checks whether @crtc is with the current mode setting output configuration
+ * in use by any connector. This doesn't mean that it is actually enabled since
+ * the DPMS state is tracked separately.
+ *
+ * Returns:
+ * True if @crtc is used, false otherwise.
+ */
+bool drm_helper_crtc_in_use(struct drm_crtc *crtc)
+{
+	struct drm_encoder *encoder;
+	struct drm_device *dev = crtc->dev;
+
+	WARN_ON(drm_drv_uses_atomic_modeset(dev));
+
+	/*
+	 * We can expect this mutex to be locked if we are not panicking.
+	 * Locking is currently fubar in the panic handler.
+	 */
+	if (!oops_in_progress)
+		WARN_ON(!mutex_is_locked(&dev->mode_config.mutex));
+
+	drm_for_each_encoder(encoder, dev)
+		if (encoder->crtc == crtc && drm_helper_encoder_in_use(encoder))
+			return true;
+	return false;
+}
+EXPORT_SYMBOL(drm_helper_crtc_in_use);
+
+static void
+drm_encoder_disable(struct drm_encoder *encoder)
+{
+	const struct drm_encoder_helper_funcs *encoder_funcs = encoder->helper_private;
+
+	if (!encoder_funcs)
+		return;
+
+	if (encoder_funcs->disable)
+		(*encoder_funcs->disable)(encoder);
+	else if (encoder_funcs->dpms)
+		(*encoder_funcs->dpms)(encoder, DRM_MODE_DPMS_OFF);
+}
+
+static void __drm_helper_disable_unused_functions(struct drm_device *dev)
+{
+	struct drm_encoder *encoder;
+	struct drm_crtc *crtc;
+
+	drm_warn_on_modeset_not_all_locked(dev);
+
+	drm_for_each_encoder(encoder, dev) {
+		if (!drm_helper_encoder_in_use(encoder)) {
+			drm_encoder_disable(encoder);
+			/* disconnect encoder from any connector */
+			encoder->crtc = NULL;
+		}
+	}
+
+	drm_for_each_crtc(crtc, dev) {
+		const struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
+
+		crtc->enabled = drm_helper_crtc_in_use(crtc);
+		if (!crtc->enabled) {
+			if (crtc_funcs->disable)
+				(*crtc_funcs->disable)(crtc);
+			else
+				(*crtc_funcs->dpms)(crtc, DRM_MODE_DPMS_OFF);
+			crtc->primary->fb = NULL;
+		}
+	}
+}
+
+/**
+ * drm_helper_disable_unused_functions - disable unused objects
+ * @dev: DRM device
+ *
+ * This function walks through the entire mode setting configuration of @dev. It
+ * will remove any CRTC links of unused encoders and encoder links of
+ * disconnected connectors. Then it will disable all unused encoders and CRTCs
+ * either by calling their disable callback if available or by calling their
+ * dpms callback with DRM_MODE_DPMS_OFF.
+ *
+ * NOTE:
+ *
+ * This function is part of the legacy modeset helper library and will cause
+ * major confusion with atomic drivers. This is because atomic helpers guarantee
+ * to never call ->disable() hooks on a disabled function, or ->enable() hooks
+ * on an enabled functions. drm_helper_disable_unused_functions() on the other
+ * hand throws such guarantees into the wind and calls disable hooks
+ * unconditionally on unused functions.
+ */
+void drm_helper_disable_unused_functions(struct drm_device *dev)
+{
+	WARN_ON(drm_drv_uses_atomic_modeset(dev));
+
+	drm_modeset_lock_all(dev);
+	__drm_helper_disable_unused_functions(dev);
+	drm_modeset_unlock_all(dev);
+}
+EXPORT_SYMBOL(drm_helper_disable_unused_functions);
+
+/*
+ * Check the CRTC we're going to map each output to vs. its current
+ * CRTC.  If they don't match, we have to disable the output and the CRTC
+ * since the driver will have to re-route things.
+ */
+static void
+drm_crtc_prepare_encoders(struct drm_device *dev)
+{
+	const struct drm_encoder_helper_funcs *encoder_funcs;
+	struct drm_encoder *encoder;
+
+	drm_for_each_encoder(encoder, dev) {
+		encoder_funcs = encoder->helper_private;
+		if (!encoder_funcs)
+			continue;
+
+		/* Disable unused encoders */
+		if (encoder->crtc == NULL)
+			drm_encoder_disable(encoder);
+	}
+}
+
+/**
+ * drm_crtc_helper_set_mode - internal helper to set a mode
+ * @crtc: CRTC to program
+ * @mode: mode to use
+ * @x: horizontal offset into the surface
+ * @y: vertical offset into the surface
+ * @old_fb: old framebuffer, for cleanup
+ *
+ * Try to set @mode on @crtc.  Give @crtc and its associated connectors a chance
+ * to fixup or reject the mode prior to trying to set it. This is an internal
+ * helper that drivers could e.g. use to update properties that require the
+ * entire output pipe to be disabled and re-enabled in a new configuration. For
+ * example for changing whether audio is enabled on a hdmi link or for changing
+ * panel fitter or dither attributes. It is also called by the
+ * drm_crtc_helper_set_config() helper function to drive the mode setting
+ * sequence.
+ *
+ * Returns:
+ * True if the mode was set successfully, false otherwise.
+ */
+bool drm_crtc_helper_set_mode(struct drm_crtc *crtc,
+			      struct drm_display_mode *mode,
+			      int x, int y,
+			      struct drm_framebuffer *old_fb)
+{
+	struct drm_device *dev = crtc->dev;
+	struct drm_display_mode *adjusted_mode, saved_mode, saved_hwmode;
+	const struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
+	const struct drm_encoder_helper_funcs *encoder_funcs;
+	int saved_x, saved_y;
+	bool saved_enabled;
+	struct drm_encoder *encoder;
+	bool ret = true;
+
+	WARN_ON(drm_drv_uses_atomic_modeset(dev));
+
+	drm_warn_on_modeset_not_all_locked(dev);
+
+	saved_enabled = crtc->enabled;
+	crtc->enabled = drm_helper_crtc_in_use(crtc);
+	if (!crtc->enabled)
+		return true;
+
+	adjusted_mode = drm_mode_duplicate(dev, mode);
+	if (!adjusted_mode) {
+		crtc->enabled = saved_enabled;
+		return false;
+	}
+
+	drm_mode_init(&saved_mode, &crtc->mode);
+	drm_mode_init(&saved_hwmode, &crtc->hwmode);
+	saved_x = crtc->x;
+	saved_y = crtc->y;
+
+	/* Update crtc values up front so the driver can rely on them for mode
+	 * setting.
+	 */
+	drm_mode_copy(&crtc->mode, mode);
+	crtc->x = x;
+	crtc->y = y;
+
+	/* Pass our mode to the connectors and the CRTC to give them a chance to
+	 * adjust it according to limitations or connector properties, and also
+	 * a chance to reject the mode entirely.
+	 */
+	drm_for_each_encoder(encoder, dev) {
+
+		if (encoder->crtc != crtc)
+			continue;
+
+		encoder_funcs = encoder->helper_private;
+		if (!encoder_funcs)
+			continue;
+
+		encoder_funcs = encoder->helper_private;
+		if (encoder_funcs->mode_fixup) {
+			if (!(ret = encoder_funcs->mode_fixup(encoder, mode,
+							      adjusted_mode))) {
+				DRM_DEBUG_KMS("Encoder fixup failed\n");
+				goto done;
+			}
+		}
+	}
+
+	if (crtc_funcs->mode_fixup) {
+		if (!(ret = crtc_funcs->mode_fixup(crtc, mode,
+						adjusted_mode))) {
+			DRM_DEBUG_KMS("CRTC fixup failed\n");
+			goto done;
+		}
+	}
+	DRM_DEBUG_KMS("[CRTC:%d:%s]\n", crtc->base.id, crtc->name);
+
+	drm_mode_copy(&crtc->hwmode, adjusted_mode);
+
+	/* Prepare the encoders and CRTCs before setting the mode. */
+	drm_for_each_encoder(encoder, dev) {
+
+		if (encoder->crtc != crtc)
+			continue;
+
+		encoder_funcs = encoder->helper_private;
+		if (!encoder_funcs)
+			continue;
+
+		/* Disable the encoders as the first thing we do. */
+		if (encoder_funcs->prepare)
+			encoder_funcs->prepare(encoder);
+	}
+
+	drm_crtc_prepare_encoders(dev);
+
+	crtc_funcs->prepare(crtc);
+
+	/* Set up the DPLL and any encoders state that needs to adjust or depend
+	 * on the DPLL.
+	 */
+	ret = !crtc_funcs->mode_set(crtc, mode, adjusted_mode, x, y, old_fb);
+	if (!ret)
+	    goto done;
+
+	drm_for_each_encoder(encoder, dev) {
+
+		if (encoder->crtc != crtc)
+			continue;
+
+		encoder_funcs = encoder->helper_private;
+		if (!encoder_funcs)
+			continue;
+
+		DRM_DEBUG_KMS("[ENCODER:%d:%s] set [MODE:%s]\n",
+			encoder->base.id, encoder->name, mode->name);
+		if (encoder_funcs->mode_set)
+			encoder_funcs->mode_set(encoder, mode, adjusted_mode);
+	}
+
+	/* Now enable the clocks, plane, pipe, and connectors that we set up. */
+	crtc_funcs->commit(crtc);
+
+	drm_for_each_encoder(encoder, dev) {
+
+		if (encoder->crtc != crtc)
+			continue;
+
+		encoder_funcs = encoder->helper_private;
+		if (!encoder_funcs)
+			continue;
+
+		if (encoder_funcs->commit)
+			encoder_funcs->commit(encoder);
+	}
+
+	/* Calculate and store various constants which
+	 * are later needed by vblank and swap-completion
+	 * timestamping. They are derived from true hwmode.
+	 */
+	drm_calc_timestamping_constants(crtc, &crtc->hwmode);
+
+	/* FIXME: add subpixel order */
+done:
+	drm_mode_destroy(dev, adjusted_mode);
+	if (!ret) {
+		crtc->enabled = saved_enabled;
+		drm_mode_copy(&crtc->mode, &saved_mode);
+		drm_mode_copy(&crtc->hwmode, &saved_hwmode);
+		crtc->x = saved_x;
+		crtc->y = saved_y;
+	}
+
+	return ret;
+}
+EXPORT_SYMBOL(drm_crtc_helper_set_mode);
+
+static void
+drm_crtc_helper_disable(struct drm_crtc *crtc)
+{
+	struct drm_device *dev = crtc->dev;
+	struct drm_connector *connector;
+	struct drm_encoder *encoder;
+
+	/* Decouple all encoders and their attached connectors from this crtc */
+	drm_for_each_encoder(encoder, dev) {
+		struct drm_connector_list_iter conn_iter;
+
+		if (encoder->crtc != crtc)
+			continue;
+
+		drm_connector_list_iter_begin(dev, &conn_iter);
+		drm_for_each_connector_iter(connector, &conn_iter) {
+			if (connector->encoder != encoder)
+				continue;
+
+			connector->encoder = NULL;
+
+			/*
+			 * drm_helper_disable_unused_functions() ought to be
+			 * doing this, but since we've decoupled the encoder
+			 * from the connector above, the required connection
+			 * between them is henceforth no longer available.
+			 */
+			connector->dpms = DRM_MODE_DPMS_OFF;
+
+			/* we keep a reference while the encoder is bound */
+			drm_connector_put(connector);
+		}
+		drm_connector_list_iter_end(&conn_iter);
+	}
+
+	__drm_helper_disable_unused_functions(dev);
+}
+
+/*
+ * For connectors that support multiple encoders, either the
+ * .atomic_best_encoder() or .best_encoder() operation must be implemented.
+ */
+struct drm_encoder *
+drm_connector_get_single_encoder(struct drm_connector *connector)
+{
+	struct drm_encoder *encoder;
+
+	WARN_ON(hweight32(connector->possible_encoders) > 1);
+	drm_connector_for_each_possible_encoder(connector, encoder)
+		return encoder;
+
+	return NULL;
+}
+
+/**
+ * drm_crtc_helper_set_config - set a new config from userspace
+ * @set: mode set configuration
+ * @ctx: lock acquire context, not used here
+ *
+ * The drm_crtc_helper_set_config() helper function implements the of
+ * &drm_crtc_funcs.set_config callback for drivers using the legacy CRTC
+ * helpers.
+ *
+ * It first tries to locate the best encoder for each connector by calling the
+ * connector @drm_connector_helper_funcs.best_encoder helper operation.
+ *
+ * After locating the appropriate encoders, the helper function will call the
+ * mode_fixup encoder and CRTC helper operations to adjust the requested mode,
+ * or reject it completely in which case an error will be returned to the
+ * application. If the new configuration after mode adjustment is identical to
+ * the current configuration the helper function will return without performing
+ * any other operation.
+ *
+ * If the adjusted mode is identical to the current mode but changes to the
+ * frame buffer need to be applied, the drm_crtc_helper_set_config() function
+ * will call the CRTC &drm_crtc_helper_funcs.mode_set_base helper operation.
+ *
+ * If the adjusted mode differs from the current mode, or if the
+ * ->mode_set_base() helper operation is not provided, the helper function
+ * performs a full mode set sequence by calling the ->prepare(), ->mode_set()
+ * and ->commit() CRTC and encoder helper operations, in that order.
+ * Alternatively it can also use the dpms and disable helper operations. For
+ * details see &struct drm_crtc_helper_funcs and struct
+ * &drm_encoder_helper_funcs.
+ *
+ * This function is deprecated.  New drivers must implement atomic modeset
+ * support, for which this function is unsuitable. Instead drivers should use
+ * drm_atomic_helper_set_config().
+ *
+ * Returns:
+ * Returns 0 on success, negative errno numbers on failure.
+ */
+int drm_crtc_helper_set_config(struct drm_mode_set *set,
+			       struct drm_modeset_acquire_ctx *ctx)
+{
+	struct drm_device *dev;
+	struct drm_crtc **save_encoder_crtcs, *new_crtc;
+	struct drm_encoder **save_connector_encoders, *new_encoder, *encoder;
+	bool mode_changed = false; /* if true do a full mode set */
+	bool fb_changed = false; /* if true and !mode_changed just do a flip */
+	struct drm_connector *connector;
+	struct drm_connector_list_iter conn_iter;
+	int count = 0, ro, fail = 0;
+	const struct drm_crtc_helper_funcs *crtc_funcs;
+	struct drm_mode_set save_set;
+	int ret;
+	int i;
+
+	DRM_DEBUG_KMS("\n");
+
+	BUG_ON(!set);
+	BUG_ON(!set->crtc);
+	BUG_ON(!set->crtc->helper_private);
+
+	/* Enforce sane interface api - has been abused by the fb helper. */
+	BUG_ON(!set->mode && set->fb);
+	BUG_ON(set->fb && set->num_connectors == 0);
+
+	crtc_funcs = set->crtc->helper_private;
+
+	dev = set->crtc->dev;
+	WARN_ON(drm_drv_uses_atomic_modeset(dev));
+
+	if (!set->mode)
+		set->fb = NULL;
+
+	if (set->fb) {
+		DRM_DEBUG_KMS("[CRTC:%d:%s] [FB:%d] #connectors=%d (x y) (%i %i)\n",
+			      set->crtc->base.id, set->crtc->name,
+			      set->fb->base.id,
+			      (int)set->num_connectors, set->x, set->y);
+	} else {
+		DRM_DEBUG_KMS("[CRTC:%d:%s] [NOFB]\n",
+			      set->crtc->base.id, set->crtc->name);
+		drm_crtc_helper_disable(set->crtc);
+		return 0;
+	}
+
+	drm_warn_on_modeset_not_all_locked(dev);
+
+	/*
+	 * Allocate space for the backup of all (non-pointer) encoder and
+	 * connector data.
+	 */
+	save_encoder_crtcs = kcalloc(dev->mode_config.num_encoder,
+				sizeof(struct drm_crtc *), GFP_KERNEL);
+	if (!save_encoder_crtcs)
+		return -ENOMEM;
+
+	save_connector_encoders = kcalloc(dev->mode_config.num_connector,
+				sizeof(struct drm_encoder *), GFP_KERNEL);
+	if (!save_connector_encoders) {
+		kfree(save_encoder_crtcs);
+		return -ENOMEM;
+	}
+
+	/*
+	 * Copy data. Note that driver private data is not affected.
+	 * Should anything bad happen only the expected state is
+	 * restored, not the drivers personal bookkeeping.
+	 */
+	count = 0;
+	drm_for_each_encoder(encoder, dev) {
+		save_encoder_crtcs[count++] = encoder->crtc;
+	}
+
+	count = 0;
+	drm_connector_list_iter_begin(dev, &conn_iter);
+	drm_for_each_connector_iter(connector, &conn_iter)
+		save_connector_encoders[count++] = connector->encoder;
+	drm_connector_list_iter_end(&conn_iter);
+
+	save_set.crtc = set->crtc;
+	save_set.mode = &set->crtc->mode;
+	save_set.x = set->crtc->x;
+	save_set.y = set->crtc->y;
+	save_set.fb = set->crtc->primary->fb;
+
+	/* We should be able to check here if the fb has the same properties
+	 * and then just flip_or_move it */
+	if (set->crtc->primary->fb != set->fb) {
+		/* If we have no fb then treat it as a full mode set */
+		if (set->crtc->primary->fb == NULL) {
+			DRM_DEBUG_KMS("crtc has no fb, full mode set\n");
+			mode_changed = true;
+		} else if (set->fb->format != set->crtc->primary->fb->format) {
+			mode_changed = true;
+		} else
+			fb_changed = true;
+	}
+
+	if (set->x != set->crtc->x || set->y != set->crtc->y)
+		fb_changed = true;
+
+	if (!drm_mode_equal(set->mode, &set->crtc->mode)) {
+		DRM_DEBUG_KMS("modes are different, full mode set\n");
+		drm_mode_debug_printmodeline(&set->crtc->mode);
+		drm_mode_debug_printmodeline(set->mode);
+		mode_changed = true;
+	}
+
+	/* take a reference on all unbound connectors in set, reuse the
+	 * already taken reference for bound connectors
+	 */
+	for (ro = 0; ro < set->num_connectors; ro++) {
+		if (set->connectors[ro]->encoder)
+			continue;
+		drm_connector_get(set->connectors[ro]);
+	}
+
+	/* a) traverse passed in connector list and get encoders for them */
+	count = 0;
+	drm_connector_list_iter_begin(dev, &conn_iter);
+	drm_for_each_connector_iter(connector, &conn_iter) {
+		const struct drm_connector_helper_funcs *connector_funcs =
+			connector->helper_private;
+		new_encoder = connector->encoder;
+		for (ro = 0; ro < set->num_connectors; ro++) {
+			if (set->connectors[ro] == connector) {
+				if (connector_funcs->best_encoder)
+					new_encoder = connector_funcs->best_encoder(connector);
+				else
+					new_encoder = drm_connector_get_single_encoder(connector);
+
+				/* if we can't get an encoder for a connector
+				   we are setting now - then fail */
+				if (new_encoder == NULL)
+					/* don't break so fail path works correct */
+					fail = 1;
+
+				if (connector->dpms != DRM_MODE_DPMS_ON) {
+					DRM_DEBUG_KMS("connector dpms not on, full mode switch\n");
+					mode_changed = true;
+				}
+
+				break;
+			}
+		}
+
+		if (new_encoder != connector->encoder) {
+			DRM_DEBUG_KMS("encoder changed, full mode switch\n");
+			mode_changed = true;
+			/* If the encoder is reused for another connector, then
+			 * the appropriate crtc will be set later.
+			 */
+			if (connector->encoder)
+				connector->encoder->crtc = NULL;
+			connector->encoder = new_encoder;
+		}
+	}
+	drm_connector_list_iter_end(&conn_iter);
+
+	if (fail) {
+		ret = -EINVAL;
+		goto fail;
+	}
+
+	count = 0;
+	drm_connector_list_iter_begin(dev, &conn_iter);
+	drm_for_each_connector_iter(connector, &conn_iter) {
+		if (!connector->encoder)
+			continue;
+
+		if (connector->encoder->crtc == set->crtc)
+			new_crtc = NULL;
+		else
+			new_crtc = connector->encoder->crtc;
+
+		for (ro = 0; ro < set->num_connectors; ro++) {
+			if (set->connectors[ro] == connector)
+				new_crtc = set->crtc;
+		}
+
+		/* Make sure the new CRTC will work with the encoder */
+		if (new_crtc &&
+		    !drm_encoder_crtc_ok(connector->encoder, new_crtc)) {
+			ret = -EINVAL;
+			drm_connector_list_iter_end(&conn_iter);
+			goto fail;
+		}
+		if (new_crtc != connector->encoder->crtc) {
+			DRM_DEBUG_KMS("crtc changed, full mode switch\n");
+			mode_changed = true;
+			connector->encoder->crtc = new_crtc;
+		}
+		if (new_crtc) {
+			DRM_DEBUG_KMS("[CONNECTOR:%d:%s] to [CRTC:%d:%s]\n",
+				      connector->base.id, connector->name,
+				      new_crtc->base.id, new_crtc->name);
+		} else {
+			DRM_DEBUG_KMS("[CONNECTOR:%d:%s] to [NOCRTC]\n",
+				      connector->base.id, connector->name);
+		}
+	}
+	drm_connector_list_iter_end(&conn_iter);
+
+	/* mode_set_base is not a required function */
+	if (fb_changed && !crtc_funcs->mode_set_base)
+		mode_changed = true;
+
+	if (mode_changed) {
+		if (drm_helper_crtc_in_use(set->crtc)) {
+			DRM_DEBUG_KMS("attempting to set mode from"
+					" userspace\n");
+			drm_mode_debug_printmodeline(set->mode);
+			set->crtc->primary->fb = set->fb;
+			if (!drm_crtc_helper_set_mode(set->crtc, set->mode,
+						      set->x, set->y,
+						      save_set.fb)) {
+				DRM_ERROR("failed to set mode on [CRTC:%d:%s]\n",
+					  set->crtc->base.id, set->crtc->name);
+				set->crtc->primary->fb = save_set.fb;
+				ret = -EINVAL;
+				goto fail;
+			}
+			DRM_DEBUG_KMS("Setting connector DPMS state to on\n");
+			for (i = 0; i < set->num_connectors; i++) {
+				DRM_DEBUG_KMS("\t[CONNECTOR:%d:%s] set DPMS on\n", set->connectors[i]->base.id,
+					      set->connectors[i]->name);
+				set->connectors[i]->funcs->dpms(set->connectors[i], DRM_MODE_DPMS_ON);
+			}
+		}
+		__drm_helper_disable_unused_functions(dev);
+	} else if (fb_changed) {
+		set->crtc->x = set->x;
+		set->crtc->y = set->y;
+		set->crtc->primary->fb = set->fb;
+		ret = crtc_funcs->mode_set_base(set->crtc,
+						set->x, set->y, save_set.fb);
+		if (ret != 0) {
+			set->crtc->x = save_set.x;
+			set->crtc->y = save_set.y;
+			set->crtc->primary->fb = save_set.fb;
+			goto fail;
+		}
+	}
+
+	kfree(save_connector_encoders);
+	kfree(save_encoder_crtcs);
+	return 0;
+
+fail:
+	/* Restore all previous data. */
+	count = 0;
+	drm_for_each_encoder(encoder, dev) {
+		encoder->crtc = save_encoder_crtcs[count++];
+	}
+
+	count = 0;
+	drm_connector_list_iter_begin(dev, &conn_iter);
+	drm_for_each_connector_iter(connector, &conn_iter)
+		connector->encoder = save_connector_encoders[count++];
+	drm_connector_list_iter_end(&conn_iter);
+
+	/* after fail drop reference on all unbound connectors in set, let
+	 * bound connectors keep their reference
+	 */
+	for (ro = 0; ro < set->num_connectors; ro++) {
+		if (set->connectors[ro]->encoder)
+			continue;
+		drm_connector_put(set->connectors[ro]);
+	}
+
+	/* Try to restore the config */
+	if (mode_changed &&
+	    !drm_crtc_helper_set_mode(save_set.crtc, save_set.mode, save_set.x,
+				      save_set.y, save_set.fb))
+		DRM_ERROR("failed to restore config after modeset failure\n");
+
+	kfree(save_connector_encoders);
+	kfree(save_encoder_crtcs);
+	return ret;
+}
+EXPORT_SYMBOL(drm_crtc_helper_set_config);
+
+static int drm_helper_choose_encoder_dpms(struct drm_encoder *encoder)
+{
+	int dpms = DRM_MODE_DPMS_OFF;
+	struct drm_connector *connector;
+	struct drm_connector_list_iter conn_iter;
+	struct drm_device *dev = encoder->dev;
+
+	drm_connector_list_iter_begin(dev, &conn_iter);
+	drm_for_each_connector_iter(connector, &conn_iter)
+		if (connector->encoder == encoder)
+			if (connector->dpms < dpms)
+				dpms = connector->dpms;
+	drm_connector_list_iter_end(&conn_iter);
+
+	return dpms;
+}
+
+/* Helper which handles bridge ordering around encoder dpms */
+static void drm_helper_encoder_dpms(struct drm_encoder *encoder, int mode)
+{
+	const struct drm_encoder_helper_funcs *encoder_funcs;
+
+	encoder_funcs = encoder->helper_private;
+	if (!encoder_funcs)
+		return;
+
+	if (encoder_funcs->dpms)
+		encoder_funcs->dpms(encoder, mode);
+}
+
+static int drm_helper_choose_crtc_dpms(struct drm_crtc *crtc)
+{
+	int dpms = DRM_MODE_DPMS_OFF;
+	struct drm_connector *connector;
+	struct drm_connector_list_iter conn_iter;
+	struct drm_device *dev = crtc->dev;
+
+	drm_connector_list_iter_begin(dev, &conn_iter);
+	drm_for_each_connector_iter(connector, &conn_iter)
+		if (connector->encoder && connector->encoder->crtc == crtc)
+			if (connector->dpms < dpms)
+				dpms = connector->dpms;
+	drm_connector_list_iter_end(&conn_iter);
+
+	return dpms;
+}
+
+/**
+ * drm_helper_connector_dpms() - connector dpms helper implementation
+ * @connector: affected connector
+ * @mode: DPMS mode
+ *
+ * The drm_helper_connector_dpms() helper function implements the
+ * &drm_connector_funcs.dpms callback for drivers using the legacy CRTC
+ * helpers.
+ *
+ * This is the main helper function provided by the CRTC helper framework for
+ * implementing the DPMS connector attribute. It computes the new desired DPMS
+ * state for all encoders and CRTCs in the output mesh and calls the
+ * &drm_crtc_helper_funcs.dpms and &drm_encoder_helper_funcs.dpms callbacks
+ * provided by the driver.
+ *
+ * This function is deprecated.  New drivers must implement atomic modeset
+ * support, where DPMS is handled in the DRM core.
+ *
+ * Returns:
+ * Always returns 0.
+ */
+int drm_helper_connector_dpms(struct drm_connector *connector, int mode)
+{
+	struct drm_encoder *encoder = connector->encoder;
+	struct drm_crtc *crtc = encoder ? encoder->crtc : NULL;
+	int old_dpms, encoder_dpms = DRM_MODE_DPMS_OFF;
+
+	WARN_ON(drm_drv_uses_atomic_modeset(connector->dev));
+
+	if (mode == connector->dpms)
+		return 0;
+
+	old_dpms = connector->dpms;
+	connector->dpms = mode;
+
+	if (encoder)
+		encoder_dpms = drm_helper_choose_encoder_dpms(encoder);
+
+	/* from off to on, do crtc then encoder */
+	if (mode < old_dpms) {
+		if (crtc) {
+			const struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
+
+			if (crtc_funcs->dpms)
+				(*crtc_funcs->dpms) (crtc,
+						     drm_helper_choose_crtc_dpms(crtc));
+		}
+		if (encoder)
+			drm_helper_encoder_dpms(encoder, encoder_dpms);
+	}
+
+	/* from on to off, do encoder then crtc */
+	if (mode > old_dpms) {
+		if (encoder)
+			drm_helper_encoder_dpms(encoder, encoder_dpms);
+		if (crtc) {
+			const struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
+
+			if (crtc_funcs->dpms)
+				(*crtc_funcs->dpms) (crtc,
+						     drm_helper_choose_crtc_dpms(crtc));
+		}
+	}
+
+	return 0;
+}
+EXPORT_SYMBOL(drm_helper_connector_dpms);
+
+/**
+ * drm_helper_resume_force_mode - force-restore mode setting configuration
+ * @dev: drm_device which should be restored
+ *
+ * Drivers which use the mode setting helpers can use this function to
+ * force-restore the mode setting configuration e.g. on resume or when something
+ * else might have trampled over the hw state (like some overzealous old BIOSen
+ * tended to do).
+ *
+ * This helper doesn't provide a error return value since restoring the old
+ * config should never fail due to resource allocation issues since the driver
+ * has successfully set the restored configuration already. Hence this should
+ * boil down to the equivalent of a few dpms on calls, which also don't provide
+ * an error code.
+ *
+ * Drivers where simply restoring an old configuration again might fail (e.g.
+ * due to slight differences in allocating shared resources when the
+ * configuration is restored in a different order than when userspace set it up)
+ * need to use their own restore logic.
+ *
+ * This function is deprecated. New drivers should implement atomic mode-
+ * setting and use the atomic suspend/resume helpers.
+ *
+ * See also:
+ * drm_atomic_helper_suspend(), drm_atomic_helper_resume()
+ */
+void drm_helper_resume_force_mode(struct drm_device *dev)
+{
+	struct drm_crtc *crtc;
+	struct drm_encoder *encoder;
+	const struct drm_crtc_helper_funcs *crtc_funcs;
+	int encoder_dpms;
+	bool ret;
+
+	WARN_ON(drm_drv_uses_atomic_modeset(dev));
+
+	drm_modeset_lock_all(dev);
+	drm_for_each_crtc(crtc, dev) {
+
+		if (!crtc->enabled)
+			continue;
+
+		ret = drm_crtc_helper_set_mode(crtc, &crtc->mode,
+					       crtc->x, crtc->y, crtc->primary->fb);
+
+		/* Restoring the old config should never fail! */
+		if (ret == false)
+			DRM_ERROR("failed to set mode on crtc %p\n", crtc);
+
+		/* Turn off outputs that were already powered off */
+		if (drm_helper_choose_crtc_dpms(crtc)) {
+			drm_for_each_encoder(encoder, dev) {
+
+				if(encoder->crtc != crtc)
+					continue;
+
+				encoder_dpms = drm_helper_choose_encoder_dpms(
+							encoder);
+
+				drm_helper_encoder_dpms(encoder, encoder_dpms);
+			}
+
+			crtc_funcs = crtc->helper_private;
+			if (crtc_funcs->dpms)
+				(*crtc_funcs->dpms) (crtc,
+						     drm_helper_choose_crtc_dpms(crtc));
+		}
+	}
+
+	/* disable the unused connectors while restoring the modesetting */
+	__drm_helper_disable_unused_functions(dev);
+	drm_modeset_unlock_all(dev);
+}
+EXPORT_SYMBOL(drm_helper_resume_force_mode);
+
+/**
+ * drm_helper_force_disable_all - Forcibly turn off all enabled CRTCs
+ * @dev: DRM device whose CRTCs to turn off
+ *
+ * Drivers may want to call this on unload to ensure that all displays are
+ * unlit and the GPU is in a consistent, low power state. Takes modeset locks.
+ *
+ * Note: This should only be used by non-atomic legacy drivers. For an atomic
+ * version look at drm_atomic_helper_shutdown().
+ *
+ * Returns:
+ * Zero on success, error code on failure.
+ */
+int drm_helper_force_disable_all(struct drm_device *dev)
+{
+	struct drm_crtc *crtc;
+	int ret = 0;
+
+	drm_modeset_lock_all(dev);
+	drm_for_each_crtc(crtc, dev)
+		if (crtc->enabled) {
+			struct drm_mode_set set = {
+				.crtc = crtc,
+			};
+
+			ret = drm_mode_set_config_internal(&set);
+			if (ret)
+				goto out;
+		}
+out:
+	drm_modeset_unlock_all(dev);
+	return ret;
+}
+EXPORT_SYMBOL(drm_helper_force_disable_all);