drm/src/drm_crtc_helper.c

/*
 * Copyright (c) 2006, 2013, Oracle and/or its affiliates. All rights reserved.
 */

/*
 * Copyright (c) 2006-2008, 2013, 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 "drmP.h"
#include "drm_crtc.h"
#include "drm_fourcc.h"
#include "drm_crtc_helper.h"
#include "drm_fb_helper.h"
#include "drm_edid.h"

/**
 * drm_helper_move_panel_connectors_to_head() - move panels to the front in the
 *                      connector list
 * @dev: drm device to operate on
 *
 * Some userspace presumes that the first connected connector is the main
 * display, where it's supposed to display e.g. the login screen. For
 * laptops, this should be the main panel. Use this function to sort all
 * (eDP/LVDS) panels to the front of the connector list, instead of
 * painstakingly trying to initialize them in the right order.
 */
void drm_helper_move_panel_connectors_to_head(struct drm_device *dev)
{
    struct drm_connector *connector, *tmp;
    struct list_head panel_list;
    struct list_head *tmp2;

    INIT_LIST_HEAD(&panel_list);

    list_for_each_entry_safe(connector, tmp, struct drm_connector,
                 &dev->mode_config.connector_list, head) {
        if (connector->connector_type == DRM_MODE_CONNECTOR_LVDS ||
            connector->connector_type == DRM_MODE_CONNECTOR_eDP)
            list_move_tail(&connector->head, &panel_list, (caddr_t)connector);
    }
    tmp2 = dev->mode_config.connector_list.next;
    list_splice(&panel_list, &dev->mode_config.connector_list, tmp2);
}

static bool drm_kms_helper_poll = true;

static void drm_mode_validate_flag(struct drm_connector *connector,
                   int flags)
{
    struct drm_display_mode *mode;

    if (flags == (DRM_MODE_FLAG_DBLSCAN | DRM_MODE_FLAG_INTERLACE))
        return;

    list_for_each_entry(mode, struct drm_display_mode, &connector->modes, head) {
        if ((mode->flags & DRM_MODE_FLAG_INTERLACE) &&
                !(flags & DRM_MODE_FLAG_INTERLACE))
            mode->status = MODE_NO_INTERLACE;
        if ((mode->flags & DRM_MODE_FLAG_DBLSCAN) &&
                !(flags & DRM_MODE_FLAG_DBLSCAN))
            mode->status = MODE_NO_DBLESCAN;
    }

    return;
}

/**
 * drm_helper_probe_connector_modes - get complete set of display modes
 * @dev: DRM device
 * @maxX: max width for modes
 * @maxY: max height for modes
 *
 * LOCKING:
 * Caller must hold mode config lock.
 *
 * Based on @dev's mode_config layout, scan all the connectors and try to detect
 * modes on them.  Modes will first be added to the connector's probed_modes
 * list, then culled (based on validity and the @maxX, @maxY parameters) and
 * put into the normal modes list.
 *
 * Intended to be used either at bootup time or when major configuration
 * changes have occurred.
 *
 * FIXME: take into account monitor limits
 *
 * RETURNS:
 * Number of modes found on @connector.
 */
int drm_helper_probe_single_connector_modes(struct drm_connector *connector,
                        uint32_t maxX, uint32_t maxY)
{
    struct drm_device *dev = connector->dev;
    struct drm_display_mode *mode;
    struct drm_connector_helper_funcs *connector_funcs =
        connector->helper_private;
    int count = 0;
    int mode_flags = 0;
    bool verbose_prune = true;

    DRM_DEBUG_KMS("[CONNECTOR:%d:%s]\n", connector->base.id,
            drm_get_connector_name(connector));
    /* set all modes to the unverified state */
    list_for_each_entry(mode, struct drm_display_mode, &connector->modes, head)
        mode->status = MODE_UNVERIFIED;

    if (connector->force) {
        if (connector->force == DRM_FORCE_ON)
            connector->status = connector_status_connected;
        else
            connector->status = connector_status_disconnected;
        if (connector->funcs->force)
            connector->funcs->force(connector);
    } else {
        connector->status = connector->funcs->detect(connector, true);
    }
    /* Re-enable polling in case the global poll config changed. */
    if (drm_kms_helper_poll != dev->mode_config.poll_running)
        drm_kms_helper_poll_enable(dev);

    dev->mode_config.poll_running = drm_kms_helper_poll;

    if (connector->status == connector_status_disconnected) {
        DRM_DEBUG_KMS("[CONNECTOR:%d:%s] disconnected\n",
            connector->base.id, drm_get_connector_name(connector));
        (void) drm_mode_connector_update_edid_property(connector, NULL);
        verbose_prune = false;
        goto prune;
    }

#ifdef CONFIG_DRM_LOAD_EDID_FIRMWARE
    count = drm_load_edid_firmware(connector);
    if (count == 0)
#endif
    count = (*connector_funcs->get_modes)(connector);

    if (count == 0 && connector->status == connector_status_connected)
        count = drm_add_modes_noedid(connector, 1024, 768);
    if (count == 0)
        goto prune;

    drm_mode_connector_list_update(connector);

    if (maxX && maxY)
        drm_mode_validate_size(dev, &connector->modes, maxX,
                       maxY, 0);

    if (connector->interlace_allowed)
        mode_flags |= DRM_MODE_FLAG_INTERLACE;
    if (connector->doublescan_allowed)
        mode_flags |= DRM_MODE_FLAG_DBLSCAN;
    drm_mode_validate_flag(connector, mode_flags);

    list_for_each_entry(mode, struct drm_display_mode, &connector->modes, head){
        if (mode->status == MODE_OK)
            mode->status = connector_funcs->mode_valid(connector,
                                   mode);
    }

prune:
    drm_mode_prune_invalid(dev, &connector->modes, verbose_prune);

    if (list_empty(&connector->modes))
        return 0;

    list_for_each_entry(mode, struct drm_display_mode, &connector->modes, head)
        mode->vrefresh = drm_mode_vrefresh(mode);

    drm_mode_sort(&connector->modes);

    DRM_DEBUG_KMS("[CONNECTOR:%d:%s] probed modes :\n", connector->base.id,
                drm_get_connector_name(connector));
    list_for_each_entry(mode, struct drm_display_mode, &connector->modes, head){
        drm_mode_set_crtcinfo(mode, CRTC_INTERLACE_HALVE_V);
        drm_mode_debug_printmodeline(mode);
    }

    return count;
}


/**
 * drm_helper_encoder_in_use - check if a given encoder is in use
 * @encoder: encoder to check
 *
 * LOCKING:
 * Caller must hold mode config lock.
 *
 * Walk @encoders's DRM device's mode_config and see if it's in use.
 *
 * RETURNS:
 * True if @encoder is part of the mode_config, false otherwise.
 */
bool drm_helper_encoder_in_use(struct drm_encoder *encoder)
{
    struct drm_connector *connector;
    struct drm_device *dev = encoder->dev;
    list_for_each_entry(connector, struct drm_connector, &dev->mode_config.connector_list, head)
        if (connector->encoder == encoder)
            return true;
    return false;
}

/**
 * drm_helper_crtc_in_use - check if a given CRTC is in a mode_config
 * @crtc: CRTC to check
 *
 * LOCKING:
 * Caller must hold mode config lock.
 *
 * Walk @crtc's DRM device's mode_config and see if it's in use.
 *
 * RETURNS:
 * True if @crtc is part of the mode_config, false otherwise.
 */
bool drm_helper_crtc_in_use(struct drm_crtc *crtc)
{
    struct drm_encoder *encoder;
    struct drm_device *dev = crtc->dev;
    /* FIXME: Locking around list access? */
    list_for_each_entry(encoder, struct drm_encoder, &dev->mode_config.encoder_list, head)
        if (encoder->crtc == crtc && drm_helper_encoder_in_use(encoder))
            return true;
    return false;
}
static void
drm_encoder_disable(struct drm_encoder *encoder)
{
    struct drm_encoder_helper_funcs *encoder_funcs = encoder->helper_private;

    if (encoder_funcs->disable)
        (*encoder_funcs->disable)(encoder);
    else
        (*encoder_funcs->dpms)(encoder, DRM_MODE_DPMS_OFF);
}

/**
 * drm_helper_disable_unused_functions - disable unused objects
 * @dev: DRM device
 *
 * LOCKING:
 * Caller must hold mode config lock.
 *
 * If an connector or CRTC isn't part of @dev's mode_config, it can be disabled
 * by calling its dpms function, which should power it off.
 */
void drm_helper_disable_unused_functions(struct drm_device *dev)
{
    struct drm_encoder *encoder;
    struct drm_connector *connector;
    struct drm_crtc *crtc;

    list_for_each_entry(connector, struct drm_connector, &dev->mode_config.connector_list, head) {
        if (!connector->encoder)
            continue;
        if (connector->status == connector_status_disconnected)
            connector->encoder = NULL;
    }

    list_for_each_entry(encoder, struct drm_encoder, &dev->mode_config.encoder_list, head) {
        if (!drm_helper_encoder_in_use(encoder)) {
            drm_encoder_disable(encoder);
            /* disconnector encoder from any connector */
            encoder->crtc = NULL;
        }
    }

    list_for_each_entry(crtc, struct drm_crtc, &dev->mode_config.crtc_list, head) {
        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->fb = NULL;
        }
    }
}


/**
 * drm_encoder_crtc_ok - can a given crtc drive a given encoder?
 * @encoder: encoder to test
 * @crtc: crtc to test
 *
 * Return false if @encoder can't be driven by @crtc, true otherwise.
 */
static bool drm_encoder_crtc_ok(struct drm_encoder *encoder,
                struct drm_crtc *crtc)
{
    struct drm_device *dev;
    struct drm_crtc *tmp;
    int crtc_mask = 1;

    if (crtc == NULL)
        DRM_ERROR("checking null crtc?\n");

    dev = crtc->dev;

    list_for_each_entry(tmp, struct drm_crtc, &dev->mode_config.crtc_list, head) {
        if (tmp == crtc)
            break;
        crtc_mask <<= 1;
    }

    if (encoder->possible_crtcs & crtc_mask)
        return true;
    return false;
}

/*
 * 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)
{
    struct drm_encoder_helper_funcs *encoder_funcs;
    struct drm_encoder *encoder;

    list_for_each_entry(encoder, struct drm_encoder, &dev->mode_config.encoder_list, head) {
        encoder_funcs = encoder->helper_private;
        /* Disable unused encoders */
        if (encoder->crtc == NULL)
            drm_encoder_disable(encoder);
        /* Disable encoders whose CRTC is about to change */
        if (encoder_funcs->get_crtc &&
            encoder->crtc != (*encoder_funcs->get_crtc)(encoder))
            drm_encoder_disable(encoder);
    }
}

/**
 * drm_crtc_set_mode - set a mode
 * @crtc: CRTC to program
 * @mode: mode to use
 * @x: width of mode
 * @y: height of mode
 * @old_fb: old framebuffer, for cleanup
 *
 * LOCKING:
 * Caller must hold mode config lock.
 *
 * 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, or 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;
    struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
    struct drm_encoder_helper_funcs *encoder_funcs;
    int saved_x, saved_y;
    struct drm_encoder *encoder;
    bool ret = true;

    crtc->enabled = drm_helper_crtc_in_use(crtc);
    if (!crtc->enabled)
        return true;

    adjusted_mode = drm_mode_duplicate(dev, mode);
    if (!adjusted_mode)
        return false;

    saved_hwmode = crtc->hwmode;
    saved_mode = crtc->mode;
    saved_x = crtc->x;
    saved_y = crtc->y;

    /* Update crtc values up front so the driver can rely on them for mode
     * setting.
     */
    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.
     */
    list_for_each_entry(encoder, struct drm_encoder, &dev->mode_config.encoder_list, head) {

        if (encoder->crtc != crtc)
            continue;
        encoder_funcs = encoder->helper_private;
        if (!(ret = encoder_funcs->mode_fixup(encoder, mode,
                              adjusted_mode))) {
            DRM_DEBUG_KMS("Encoder fixup failed\n");
            goto done;
        }
    }

    if (!(ret = crtc_funcs->mode_fixup(crtc, mode, adjusted_mode))) {
        DRM_DEBUG_KMS("CRTC fixup failed\n");
        goto done;
    }
    DRM_DEBUG_KMS("[CRTC:%d]\n", crtc->base.id);

    /* Prepare the encoders and CRTCs before setting the mode. */
    list_for_each_entry(encoder, struct drm_encoder, &dev->mode_config.encoder_list, head) {

        if (encoder->crtc != crtc)
            continue;
        encoder_funcs = encoder->helper_private;
        /* Disable the encoders as the first thing we do. */
        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;

    list_for_each_entry(encoder, struct drm_encoder, &dev->mode_config.encoder_list, head) {

        if (encoder->crtc != crtc)
            continue;

        DRM_DEBUG_KMS("[ENCODER:%d:%s] set [MODE:%d:%s]\n",
            encoder->base.id, drm_get_encoder_name(encoder),
            mode->base.id, mode->name);
        encoder_funcs = encoder->helper_private;
        encoder_funcs->mode_set(encoder, mode, adjusted_mode);
    }

    /* Now enable the clocks, plane, pipe, and connectors that we set up. */
    crtc_funcs->commit(crtc);

    list_for_each_entry(encoder, struct drm_encoder, &dev->mode_config.encoder_list, head) {

        if (encoder->crtc != crtc)
            continue;

        encoder_funcs = encoder->helper_private;
        encoder_funcs->commit(encoder);

    }

    /* Store real post-adjustment hardware mode. */
    crtc->hwmode = *adjusted_mode;

    /* 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);

    /* FIXME: add subpixel order */
done:
    drm_mode_destroy(dev, adjusted_mode);
    if (!ret) {
        crtc->hwmode = saved_hwmode;
        crtc->mode = saved_mode;
        crtc->x = saved_x;
        crtc->y = saved_y;
    }

    return ret;
}

static int
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 */
    list_for_each_entry(encoder, struct drm_encoder, &dev->mode_config.encoder_list, head) {
        if (encoder->crtc != crtc)
            continue;

        list_for_each_entry(connector, struct drm_connector, &dev->mode_config.connector_list, head) {
            if (connector->encoder != encoder)
                continue;

            connector->encoder = NULL;
        }
    }

    drm_helper_disable_unused_functions(dev);
    return 0;
}

/**
 * drm_crtc_helper_set_config - set a new config from userspace
 * @set: mode set configuration
 *
 * LOCKING:
 * Caller must hold mode config lock.
 *
 * Setup a new configuration, provided by the upper layers (either an ioctl call
 * from userspace or internally e.g. from the fbdev suppport code) in @set, and
 * enable it. This is the main helper functions for drivers that implement
 * kernel mode setting with the crtc helper functions and the assorted
 * ->prepare(), ->modeset() and ->commit() helper callbacks.
 *
 * RETURNS:
 * Zero. (FIXME)
 */
int drm_crtc_helper_set_config(struct drm_mode_set *set)
{
    struct drm_device *dev;
    struct drm_crtc *save_crtcs, *new_crtc, *crtc;
    struct drm_encoder *save_encoders, *new_encoder, *encoder;
    struct drm_framebuffer *old_fb = NULL;
    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 *save_connectors, *connector;
    int count = 0, ro, fail = 0;
    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;

    if (!set->mode)
        set->fb = NULL;

    if (set->fb) {
        DRM_DEBUG_KMS("[CRTC:%d] [FB:%d] #connectors=%d (x y) (%i %i)\n",
            set->crtc->base.id, set->fb->base.id,
            (int)set->num_connectors, set->x, set->y);
    } else {
        DRM_DEBUG_KMS("[CRTC:%d] [NOFB]\n", set->crtc->base.id);
        return drm_crtc_helper_disable(set->crtc);
    }

    dev = set->crtc->dev;

    /* Allocate space for the backup of all (non-pointer) crtc, encoder and
     * connector data. */
    save_crtcs = kzalloc(dev->mode_config.num_crtc *
                 sizeof(struct drm_crtc), GFP_KERNEL);
    if (!save_crtcs)
        return -ENOMEM;

    save_encoders = kzalloc(dev->mode_config.num_encoder *
                sizeof(struct drm_encoder), GFP_KERNEL);
    if (!save_encoders) {
        kfree(save_crtcs, dev->mode_config.num_crtc * sizeof(struct drm_crtc));
        return -ENOMEM;
    }

    save_connectors = kzalloc(dev->mode_config.num_connector *
                sizeof(struct drm_connector), GFP_KERNEL);
    if (!save_connectors) {
        kfree(save_crtcs, dev->mode_config.num_crtc * sizeof(struct drm_crtc));
        kfree(save_encoders, dev->mode_config.num_encoder * sizeof(struct drm_encoder));
        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;
    list_for_each_entry(crtc, struct drm_crtc, &dev->mode_config.crtc_list, head) {
        save_crtcs[count++] = *crtc;
    }

    count = 0;
    list_for_each_entry(encoder, struct drm_encoder, &dev->mode_config.encoder_list, head) {
        save_encoders[count++] = *encoder;
    }

    count = 0;
    list_for_each_entry(connector, struct drm_connector, &dev->mode_config.connector_list, head) {
        save_connectors[count++] = *connector;
    }

    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->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->fb != set->fb) {
        /* If we have no fb then treat it as a full mode set */
        if (set->crtc->fb == NULL) {
            DRM_DEBUG_KMS("crtc has no fb, full mode set\n");
            mode_changed = true;
        } else if (set->fb == NULL) {
            mode_changed = true;
        } else if (set->fb->pixel_format !=
               set->crtc->fb->pixel_format) {
            mode_changed = true;
        } else
            fb_changed = true;
    }

    if (set->x != set->crtc->x || set->y != set->crtc->y)
        fb_changed = true;

    if (set->mode && !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;
    }

    /* a) traverse passed in connector list and get encoders for them */
    count = 0;
    list_for_each_entry(connector, struct drm_connector, &dev->mode_config.connector_list, head) {
        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) {
                new_encoder = connector_funcs->best_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;
                break;
/*
                if (connector->dpms != DRM_MODE_DPMS_ON) {
                    DRM_DEBUG_KMS("connector dpms not on, full mode switch\n");
                    mode_changed = true;
                }
*/
            }
        }

        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;
        }
    }

    if (fail) {
        ret = -EINVAL;
        goto fail;
    }

    count = 0;
    list_for_each_entry(connector, struct drm_connector, &dev->mode_config.connector_list, head) {
        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;
            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]\n",
                connector->base.id, drm_get_connector_name(connector),
                new_crtc->base.id);
        } else {
            DRM_DEBUG_KMS("[CONNECTOR:%d:%s] to [NOCRTC]\n",
                connector->base.id, drm_get_connector_name(connector));
        }
    }

    /* mode_set_base is not a required function */
    if (fb_changed && !crtc_funcs->mode_set_base)
        mode_changed = true;

    if (mode_changed) {
        set->crtc->enabled = drm_helper_crtc_in_use(set->crtc);
        if (set->crtc->enabled) {
            DRM_DEBUG_KMS("attempting to set mode from"
                    " userspace\n");
            drm_mode_debug_printmodeline(set->mode);
            old_fb = set->crtc->fb;
            set->crtc->fb = set->fb;
            if (!drm_crtc_helper_set_mode(set->crtc, set->mode,
                              set->x, set->y,
                              old_fb)) {
                DRM_ERROR("failed to set mode on [CRTC:%d]\n",
                    set->crtc->base.id);
                set->crtc->fb = old_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,
                          drm_get_connector_name(set->connectors[i]));
                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;

        old_fb = set->crtc->fb;
        if (set->crtc->fb != set->fb)
            set->crtc->fb = set->fb;
        ret = crtc_funcs->mode_set_base(set->crtc,
                        set->x, set->y, old_fb);
        if (ret != 0) {
            set->crtc->fb = old_fb;
            goto fail;
        }
    }

    kfree(save_connectors, dev->mode_config.num_connector * sizeof(struct drm_connector));
    kfree(save_encoders, dev->mode_config.num_encoder * sizeof(struct drm_encoder));
    kfree(save_crtcs, dev->mode_config.num_crtc * sizeof(struct drm_crtc));
    return 0;

fail:
    /* Restore all previous data. */
    count = 0;
    list_for_each_entry(crtc, struct drm_crtc, &dev->mode_config.crtc_list, head) {
        *crtc = save_crtcs[count++];
    }

    count = 0;
    list_for_each_entry(encoder, struct drm_encoder, &dev->mode_config.encoder_list, head) {
        *encoder = save_encoders[count++];
    }

    count = 0;
    list_for_each_entry(connector, struct drm_connector, &dev->mode_config.connector_list, head) {
        *connector = save_connectors[count++];
    }

    /* 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_connectors, dev->mode_config.num_connector * sizeof(struct drm_connector));
    kfree(save_encoders, dev->mode_config.num_encoder * sizeof(struct drm_encoder));
    kfree(save_crtcs, dev->mode_config.num_crtc * sizeof(struct drm_crtc));
    return ret;
}


static int drm_helper_choose_encoder_dpms(struct drm_encoder *encoder)
{
    int dpms = DRM_MODE_DPMS_OFF;
    struct drm_connector *connector;
    struct drm_device *dev = encoder->dev;

    list_for_each_entry(connector, struct drm_connector, &dev->mode_config.connector_list, head)
        if (connector->encoder == encoder)
            if (connector->dpms < dpms)
                dpms = connector->dpms;
    return dpms;
}

static int drm_helper_choose_crtc_dpms(struct drm_crtc *crtc)
{
    int dpms = DRM_MODE_DPMS_OFF;
    struct drm_connector *connector;
    struct drm_device *dev = crtc->dev;

    list_for_each_entry(connector, struct drm_connector, &dev->mode_config.connector_list, head)
        if (connector->encoder && connector->encoder->crtc == crtc)
            if (connector->dpms < dpms)
                dpms = connector->dpms;
    return dpms;
}

/**
 * drm_helper_connector_dpms
 * @connector affected connector
 * @mode DPMS mode
 *
 * 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 ->dpms()
 * callback provided by the driver appropriately.
 */
void 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;

    if (mode == connector->dpms)
        return;

    old_dpms = connector->dpms;
    connector->dpms = mode;

    /* from off to on, do crtc then encoder */
    if (mode < old_dpms) {
        if (crtc) {
            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) {
            struct drm_encoder_helper_funcs *encoder_funcs = encoder->helper_private;
            if (encoder_funcs->dpms)
                (*encoder_funcs->dpms) (encoder,
                            drm_helper_choose_encoder_dpms(encoder));
        }
    }

    /* from on to off, do encoder then crtc */
    if (mode > old_dpms) {
        if (encoder) {
            struct drm_encoder_helper_funcs *encoder_funcs = encoder->helper_private;
            if (encoder_funcs->dpms)
                (*encoder_funcs->dpms) (encoder,
                            drm_helper_choose_encoder_dpms(encoder));
        }
        if (crtc) {
            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;
}


int drm_helper_mode_fill_fb_struct(struct drm_framebuffer *fb,
                   struct drm_mode_fb_cmd2 *mode_cmd)
{
    int i;

    fb->width = mode_cmd->width;
    fb->height = mode_cmd->height;
    for (i = 0; i < 4; i++) {
        fb->pitches[i] = mode_cmd->pitches[i];
        fb->offsets[i] = mode_cmd->offsets[i];
    }
    drm_fb_get_bpp_depth(mode_cmd->pixel_format, &fb->depth,
                    &fb->bits_per_pixel);
    fb->pixel_format = mode_cmd->pixel_format;

    return 0;
}

void drm_helper_resume_force_mode(struct drm_device *dev)
{
    struct drm_crtc *crtc;
    struct drm_encoder *encoder;
    struct drm_encoder_helper_funcs *encoder_funcs;
    struct drm_crtc_helper_funcs *crtc_funcs;
    int ret;

    list_for_each_entry(crtc, struct drm_crtc, &dev->mode_config.crtc_list, head) {

        if (!crtc->enabled)
            continue;

        ret = drm_crtc_helper_set_mode(crtc, &crtc->mode,
                           crtc->x, crtc->y, crtc->fb);

        if (ret == false)
            DRM_ERROR("failed to set mode on crtc %p\n", (void *)crtc);

        /* Turn off outputs that were already powered off */
        if (drm_helper_choose_crtc_dpms(crtc)) {
            list_for_each_entry(encoder, struct drm_encoder, &dev->mode_config.encoder_list, head) {

                if(encoder->crtc != crtc)
                    continue;

                encoder_funcs = encoder->helper_private;
                if (encoder_funcs->dpms)
                    (*encoder_funcs->dpms) (encoder,
                                drm_helper_choose_encoder_dpms(encoder));
            }

            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);
}

void drm_kms_helper_hotplug_event(struct drm_device *dev)
{
    if (dev->mode_config.funcs->output_poll_changed)
        dev->mode_config.funcs->output_poll_changed(dev);
}
#define DRM_OUTPUT_POLL_PERIOD (10*DRM_HZ)
static void
output_poll_execute(struct work_struct *work)
{
    struct drm_device *dev = container_of(work, struct drm_device,
                        output_poll_work);
    struct drm_connector *connector;
    enum drm_connector_status old_status;
    bool repoll = false, changed = false;

    if (!drm_kms_helper_poll)
        return;

    mutex_lock(&dev->mode_config.mutex);
    list_for_each_entry(connector, struct drm_connector, &dev->mode_config.connector_list, head) {

        /* Ignore forced connectors. */
        if (connector->force)
            continue;

        /* Ignore HPD capable connectors and connectors where we don't
         * want any hotplug detection at all for polling. */
        if (!connector->polled || connector->polled == DRM_CONNECTOR_POLL_HPD)
            continue;

            repoll = true;

        old_status = connector->status;
        /* if we are connected and don't want to poll for disconnect
           skip it */
        if (old_status == connector_status_connected &&
            !(connector->polled & DRM_CONNECTOR_POLL_DISCONNECT))
            continue;

        connector->status = connector->funcs->detect(connector, false);
        if (old_status != connector->status) {
            const char *old, *new;

            old = drm_get_connector_status_name(old_status);
            new = drm_get_connector_status_name(connector->status);

            DRM_DEBUG_KMS("[CONNECTOR:%d:%s] "
                      "status updated from %s to %s\n",
                      connector->base.id,
                      drm_get_connector_name(connector),
                      old, new);

            changed = true;
        }
    }

    mutex_unlock(&dev->mode_config.mutex);

    if (changed)
        drm_kms_helper_hotplug_event(dev);

    if (repoll)
        test_set_timer(&dev->output_poll_timer, DRM_OUTPUT_POLL_PERIOD);
}

void
output_poll_execute_timer(void *device)
{
    struct drm_device *dev = (struct drm_device *)device;
    (void) queue_work(dev->drm_wq, &dev->output_poll_work);
}

void drm_kms_helper_poll_disable(struct drm_device *dev)
{
    if (!dev->mode_config.poll_enabled)
        return;
    del_timer_sync(&dev->output_poll_timer);
}

void drm_kms_helper_poll_enable(struct drm_device *dev)
{
    bool poll = false;
    struct drm_connector *connector;

    if (!dev->mode_config.poll_enabled || !drm_kms_helper_poll)
        return;

    list_for_each_entry(connector, struct drm_connector, &dev->mode_config.connector_list, head) {
        if (connector->polled)
            poll = true;
    }

    if (poll)
        test_set_timer(&dev->output_poll_timer, DRM_OUTPUT_POLL_PERIOD);
}

void drm_kms_helper_poll_init(struct drm_device *dev)
{
    INIT_WORK(&dev->output_poll_work, output_poll_execute);
    setup_timer(&dev->output_poll_timer, output_poll_execute_timer,
            (void *)dev);

    dev->mode_config.poll_enabled = true;

    drm_kms_helper_poll_enable(dev);
}

void drm_kms_helper_poll_fini(struct drm_device *dev)
{
    drm_kms_helper_poll_disable(dev);
}

void drm_helper_hpd_irq_event(struct drm_device *dev)
{
    if (!dev->mode_config.poll_enabled)
        return;

    /* kill timer and schedule immediate execution, this doesn't block */
    del_timer_sync(&dev->output_poll_timer);
    cancel_delayed_work(dev->drm_wq);
    if (drm_kms_helper_poll)
        test_set_timer(&dev->output_poll_timer, 0);
}