drm_fb_helper.c

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/*
 * Copyright (c) 2006-2009 Red Hat Inc.
 * Copyright (c) 2006-2008 Intel Corporation
 * Copyright (c) 2007 Dave Airlie <[email protected]>
 *
 * DRM framebuffer helper 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:
 *      Dave Airlie <[email protected]>
 *      Jesse Barnes <[email protected]>
 */
#include <linux/kernel.h>
#include <linux/sysrq.h>
#include <linux/slab.h>
#include <linux/fb.h>
#include <linux/module.h>
#include <drm/drmP.h>
#include <drm/drm_crtc.h>
#include <drm/drm_fb_helper.h>
#include <drm/drm_crtc_helper.h>

MODULE_AUTHOR("David Airlie, Jesse Barnes");
MODULE_DESCRIPTION("DRM KMS helper");
MODULE_LICENSE("GPL and additional rights");

static LIST_HEAD(kernel_fb_helper_list);

/* simple single crtc case helper function */
int drm_fb_helper_single_add_all_connectors(struct drm_fb_helper *fb_helper)
{
    struct drm_device *dev = fb_helper->dev;
    struct drm_connector *connector;
    int i;

    list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
        struct drm_fb_helper_connector *fb_helper_connector;

        fb_helper_connector = kzalloc(sizeof(struct drm_fb_helper_connector), GFP_KERNEL);
        if (!fb_helper_connector)
            goto fail;

        fb_helper_connector->connector = connector;
        fb_helper->connector_info[fb_helper->connector_count++] = fb_helper_connector;
    }
    return 0;
fail:
    for (i = 0; i < fb_helper->connector_count; i++) {
        kfree(fb_helper->connector_info[i]);
        fb_helper->connector_info[i] = NULL;
    }
    fb_helper->connector_count = 0;
    return -ENOMEM;
}
EXPORT_SYMBOL(drm_fb_helper_single_add_all_connectors);

static int drm_fb_helper_parse_command_line(struct drm_fb_helper *fb_helper)
{
    struct drm_fb_helper_connector *fb_helper_conn;
    int i;

    for (i = 0; i < fb_helper->connector_count; i++) {
        struct drm_cmdline_mode *mode;
        struct drm_connector *connector;
        char *option = NULL;

        fb_helper_conn = fb_helper->connector_info[i];
        connector = fb_helper_conn->connector;
        mode = &fb_helper_conn->cmdline_mode;

        /* do something on return - turn off connector maybe */
        if (fb_get_options(drm_get_connector_name(connector), &option))
            continue;

        if (drm_mode_parse_command_line_for_connector(option,
                                  connector,
                                  mode)) {
            if (mode->force) {
                const char *s;
                switch (mode->force) {
                case DRM_FORCE_OFF: s = "OFF"; break;
                case DRM_FORCE_ON_DIGITAL: s = "ON - dig"; break;
                default:
                case DRM_FORCE_ON: s = "ON"; break;
                }

                DRM_INFO("forcing %s connector %s\n",
                     drm_get_connector_name(connector), s);
                connector->force = mode->force;
            }

            DRM_DEBUG_KMS("cmdline mode for connector %s %dx%d@%dHz%s%s%s\n",
                      drm_get_connector_name(connector),
                      mode->xres, mode->yres,
                      mode->refresh_specified ? mode->refresh : 60,
                      mode->rb ? " reduced blanking" : "",
                      mode->margins ? " with margins" : "",
                      mode->interlace ?  " interlaced" : "");
        }

    }
    return 0;
}

static void drm_fb_helper_save_lut_atomic(struct drm_crtc *crtc, struct drm_fb_helper *helper)
{
    uint16_t *r_base, *g_base, *b_base;
    int i;

    r_base = crtc->gamma_store;
    g_base = r_base + crtc->gamma_size;
    b_base = g_base + crtc->gamma_size;

    for (i = 0; i < crtc->gamma_size; i++)
        helper->funcs->gamma_get(crtc, &r_base[i], &g_base[i], &b_base[i], i);
}

static void drm_fb_helper_restore_lut_atomic(struct drm_crtc *crtc)
{
    uint16_t *r_base, *g_base, *b_base;

    if (crtc->funcs->gamma_set == NULL)
        return;

    r_base = crtc->gamma_store;
    g_base = r_base + crtc->gamma_size;
    b_base = g_base + crtc->gamma_size;

    crtc->funcs->gamma_set(crtc, r_base, g_base, b_base, 0, crtc->gamma_size);
}

int drm_fb_helper_debug_enter(struct fb_info *info)
{
    struct drm_fb_helper *helper = info->par;
    struct drm_crtc_helper_funcs *funcs;
    int i;

    if (list_empty(&kernel_fb_helper_list))
        return false;

    list_for_each_entry(helper, &kernel_fb_helper_list, kernel_fb_list) {
        for (i = 0; i < helper->crtc_count; i++) {
            struct drm_mode_set *mode_set =
                &helper->crtc_info[i].mode_set;

            if (!mode_set->crtc->enabled)
                continue;

            funcs = mode_set->crtc->helper_private;
            drm_fb_helper_save_lut_atomic(mode_set->crtc, helper);
            funcs->mode_set_base_atomic(mode_set->crtc,
                            mode_set->fb,
                            mode_set->x,
                            mode_set->y,
                            ENTER_ATOMIC_MODE_SET);
        }
    }

    return 0;
}
EXPORT_SYMBOL(drm_fb_helper_debug_enter);

/* Find the real fb for a given fb helper CRTC */
static struct drm_framebuffer *drm_mode_config_fb(struct drm_crtc *crtc)
{
    struct drm_device *dev = crtc->dev;
    struct drm_crtc *c;

    list_for_each_entry(c, &dev->mode_config.crtc_list, head) {
        if (crtc->base.id == c->base.id)
            return c->fb;
    }

    return NULL;
}

int drm_fb_helper_debug_leave(struct fb_info *info)
{
    struct drm_fb_helper *helper = info->par;
    struct drm_crtc *crtc;
    struct drm_crtc_helper_funcs *funcs;
    struct drm_framebuffer *fb;
    int i;

    for (i = 0; i < helper->crtc_count; i++) {
        struct drm_mode_set *mode_set = &helper->crtc_info[i].mode_set;
        crtc = mode_set->crtc;
        funcs = crtc->helper_private;
        fb = drm_mode_config_fb(crtc);

        if (!crtc->enabled)
            continue;

        if (!fb) {
            DRM_ERROR("no fb to restore??\n");
            continue;
        }

        drm_fb_helper_restore_lut_atomic(mode_set->crtc);
        funcs->mode_set_base_atomic(mode_set->crtc, fb, crtc->x,
                        crtc->y, LEAVE_ATOMIC_MODE_SET);
    }

    return 0;
}
EXPORT_SYMBOL(drm_fb_helper_debug_leave);

bool drm_fb_helper_restore_fbdev_mode(struct drm_fb_helper *fb_helper)
{
    bool error = false;
    int i, ret;
    for (i = 0; i < fb_helper->crtc_count; i++) {
        struct drm_mode_set *mode_set = &fb_helper->crtc_info[i].mode_set;
        ret = mode_set->crtc->funcs->set_config(mode_set);
        if (ret)
            error = true;
    }
    return error;
}
EXPORT_SYMBOL(drm_fb_helper_restore_fbdev_mode);

static bool drm_fb_helper_force_kernel_mode(void)
{
    bool ret, error = false;
    struct drm_fb_helper *helper;

    if (list_empty(&kernel_fb_helper_list))
        return false;

    list_for_each_entry(helper, &kernel_fb_helper_list, kernel_fb_list) {
        if (helper->dev->switch_power_state == DRM_SWITCH_POWER_OFF)
            continue;

        ret = drm_fb_helper_restore_fbdev_mode(helper);
        if (ret)
            error = true;
    }
    return error;
}

int drm_fb_helper_panic(struct notifier_block *n, unsigned long ununsed,
            void *panic_str)
{
    /*
     * It's a waste of time and effort to switch back to text console
     * if the kernel should reboot before panic messages can be seen.
     */
    if (panic_timeout < 0)
        return 0;

    printk(KERN_ERR "panic occurred, switching back to text console\n");
    return drm_fb_helper_force_kernel_mode();
}
EXPORT_SYMBOL(drm_fb_helper_panic);

static struct notifier_block paniced = {
    .notifier_call = drm_fb_helper_panic,
};

void drm_fb_helper_restore(void)
{
    bool ret;
    ret = drm_fb_helper_force_kernel_mode();
    if (ret == true)
        DRM_ERROR("Failed to restore crtc configuration\n");
}
EXPORT_SYMBOL(drm_fb_helper_restore);

#ifdef CONFIG_MAGIC_SYSRQ
static void drm_fb_helper_restore_work_fn(struct work_struct *ignored)
{
    drm_fb_helper_restore();
}
static DECLARE_WORK(drm_fb_helper_restore_work, drm_fb_helper_restore_work_fn);

static void drm_fb_helper_sysrq(int dummy1)
{
    schedule_work(&drm_fb_helper_restore_work);
}

static struct sysrq_key_op sysrq_drm_fb_helper_restore_op = {
    .handler = drm_fb_helper_sysrq,
    .help_msg = "force-fb(V)",
    .action_msg = "Restore framebuffer console",
};
#else
static struct sysrq_key_op sysrq_drm_fb_helper_restore_op = { };
#endif

static void drm_fb_helper_dpms(struct fb_info *info, int dpms_mode)
{
    struct drm_fb_helper *fb_helper = info->par;
    struct drm_device *dev = fb_helper->dev;
    struct drm_crtc *crtc;
    struct drm_connector *connector;
    int i, j;

    /*
     * For each CRTC in this fb, turn the connectors on/off.
     */
    mutex_lock(&dev->mode_config.mutex);
    for (i = 0; i < fb_helper->crtc_count; i++) {
        crtc = fb_helper->crtc_info[i].mode_set.crtc;

        if (!crtc->enabled)
            continue;

        /* Walk the connectors & encoders on this fb turning them on/off */
        for (j = 0; j < fb_helper->connector_count; j++) {
            connector = fb_helper->connector_info[j]->connector;
            connector->funcs->dpms(connector, dpms_mode);
            drm_connector_property_set_value(connector,
                dev->mode_config.dpms_property, dpms_mode);
        }
    }
    mutex_unlock(&dev->mode_config.mutex);
}

int drm_fb_helper_blank(int blank, struct fb_info *info)
{
    switch (blank) {
    /* Display: On; HSync: On, VSync: On */
    case FB_BLANK_UNBLANK:
        drm_fb_helper_dpms(info, DRM_MODE_DPMS_ON);
        break;
    /* Display: Off; HSync: On, VSync: On */
    case FB_BLANK_NORMAL:
        drm_fb_helper_dpms(info, DRM_MODE_DPMS_STANDBY);
        break;
    /* Display: Off; HSync: Off, VSync: On */
    case FB_BLANK_HSYNC_SUSPEND:
        drm_fb_helper_dpms(info, DRM_MODE_DPMS_STANDBY);
        break;
    /* Display: Off; HSync: On, VSync: Off */
    case FB_BLANK_VSYNC_SUSPEND:
        drm_fb_helper_dpms(info, DRM_MODE_DPMS_SUSPEND);
        break;
    /* Display: Off; HSync: Off, VSync: Off */
    case FB_BLANK_POWERDOWN:
        drm_fb_helper_dpms(info, DRM_MODE_DPMS_OFF);
        break;
    }
    return 0;
}
EXPORT_SYMBOL(drm_fb_helper_blank);

static void drm_fb_helper_crtc_free(struct drm_fb_helper *helper)
{
    int i;

    for (i = 0; i < helper->connector_count; i++)
        kfree(helper->connector_info[i]);
    kfree(helper->connector_info);
    for (i = 0; i < helper->crtc_count; i++) {
        kfree(helper->crtc_info[i].mode_set.connectors);
        if (helper->crtc_info[i].mode_set.mode)
            drm_mode_destroy(helper->dev, helper->crtc_info[i].mode_set.mode);
    }
    kfree(helper->crtc_info);
}

int drm_fb_helper_init(struct drm_device *dev,
               struct drm_fb_helper *fb_helper,
               int crtc_count, int max_conn_count)
{
    struct drm_crtc *crtc;
    int i;

    fb_helper->dev = dev;

    INIT_LIST_HEAD(&fb_helper->kernel_fb_list);

    fb_helper->crtc_info = kcalloc(crtc_count, sizeof(struct drm_fb_helper_crtc), GFP_KERNEL);
    if (!fb_helper->crtc_info)
        return -ENOMEM;

    fb_helper->crtc_count = crtc_count;
    fb_helper->connector_info = kcalloc(dev->mode_config.num_connector, sizeof(struct drm_fb_helper_connector *), GFP_KERNEL);
    if (!fb_helper->connector_info) {
        kfree(fb_helper->crtc_info);
        return -ENOMEM;
    }
    fb_helper->connector_count = 0;

    for (i = 0; i < crtc_count; i++) {
        fb_helper->crtc_info[i].mode_set.connectors =
            kcalloc(max_conn_count,
                sizeof(struct drm_connector *),
                GFP_KERNEL);

        if (!fb_helper->crtc_info[i].mode_set.connectors)
            goto out_free;
        fb_helper->crtc_info[i].mode_set.num_connectors = 0;
    }

    i = 0;
    list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
        fb_helper->crtc_info[i].mode_set.crtc = crtc;
        i++;
    }

    return 0;
out_free:
    drm_fb_helper_crtc_free(fb_helper);
    return -ENOMEM;
}
EXPORT_SYMBOL(drm_fb_helper_init);

void drm_fb_helper_fini(struct drm_fb_helper *fb_helper)
{
    if (!list_empty(&fb_helper->kernel_fb_list)) {
        list_del(&fb_helper->kernel_fb_list);
        if (list_empty(&kernel_fb_helper_list)) {
            printk(KERN_INFO "drm: unregistered panic notifier\n");
            atomic_notifier_chain_unregister(&panic_notifier_list,
                             &paniced);
            unregister_sysrq_key('v', &sysrq_drm_fb_helper_restore_op);
        }
    }

    drm_fb_helper_crtc_free(fb_helper);

}
EXPORT_SYMBOL(drm_fb_helper_fini);

static int setcolreg(struct drm_crtc *crtc, u16 red, u16 green,
             u16 blue, u16 regno, struct fb_info *info)
{
    struct drm_fb_helper *fb_helper = info->par;
    struct drm_framebuffer *fb = fb_helper->fb;
    int pindex;

    if (info->fix.visual == FB_VISUAL_TRUECOLOR) {
        u32 *palette;
        u32 value;
        /* place color in psuedopalette */
        if (regno > 16)
            return -EINVAL;
        palette = (u32 *)info->pseudo_palette;
        red >>= (16 - info->var.red.length);
        green >>= (16 - info->var.green.length);
        blue >>= (16 - info->var.blue.length);
        value = (red << info->var.red.offset) |
            (green << info->var.green.offset) |
            (blue << info->var.blue.offset);
        if (info->var.transp.length > 0) {
            u32 mask = (1 << info->var.transp.length) - 1;
            mask <<= info->var.transp.offset;
            value |= mask;
        }
        palette[regno] = value;
        return 0;
    }

    pindex = regno;

    if (fb->bits_per_pixel == 16) {
        pindex = regno << 3;

        if (fb->depth == 16 && regno > 63)
            return -EINVAL;
        if (fb->depth == 15 && regno > 31)
            return -EINVAL;

        if (fb->depth == 16) {
            u16 r, g, b;
            int i;
            if (regno < 32) {
                for (i = 0; i < 8; i++)
                    fb_helper->funcs->gamma_set(crtc, red,
                        green, blue, pindex + i);
            }

            fb_helper->funcs->gamma_get(crtc, &r,
                            &g, &b,
                            pindex >> 1);

            for (i = 0; i < 4; i++)
                fb_helper->funcs->gamma_set(crtc, r,
                                green, b,
                                (pindex >> 1) + i);
        }
    }

    if (fb->depth != 16)
        fb_helper->funcs->gamma_set(crtc, red, green, blue, pindex);
    return 0;
}

int drm_fb_helper_setcmap(struct fb_cmap *cmap, struct fb_info *info)
{
    struct drm_fb_helper *fb_helper = info->par;
    struct drm_crtc_helper_funcs *crtc_funcs;
    u16 *red, *green, *blue, *transp;
    struct drm_crtc *crtc;
    int i, j, rc = 0;
    int start;

    for (i = 0; i < fb_helper->crtc_count; i++) {
        crtc = fb_helper->crtc_info[i].mode_set.crtc;
        crtc_funcs = crtc->helper_private;

        red = cmap->red;
        green = cmap->green;
        blue = cmap->blue;
        transp = cmap->transp;
        start = cmap->start;

        for (j = 0; j < cmap->len; j++) {
            u16 hred, hgreen, hblue, htransp = 0xffff;

            hred = *red++;
            hgreen = *green++;
            hblue = *blue++;

            if (transp)
                htransp = *transp++;

            rc = setcolreg(crtc, hred, hgreen, hblue, start++, info);
            if (rc)
                return rc;
        }
        crtc_funcs->load_lut(crtc);
    }
    return rc;
}
EXPORT_SYMBOL(drm_fb_helper_setcmap);

int drm_fb_helper_check_var(struct fb_var_screeninfo *var,
                struct fb_info *info)
{
    struct drm_fb_helper *fb_helper = info->par;
    struct drm_framebuffer *fb = fb_helper->fb;
    int depth;

    if (var->pixclock != 0 || in_dbg_master())
        return -EINVAL;

    /* Need to resize the fb object !!! */
    if (var->bits_per_pixel > fb->bits_per_pixel ||
        var->xres > fb->width || var->yres > fb->height ||
        var->xres_virtual > fb->width || var->yres_virtual > fb->height) {
        DRM_DEBUG("fb userspace requested width/height/bpp is greater than current fb "
              "request %dx%d-%d (virtual %dx%d) > %dx%d-%d\n",
              var->xres, var->yres, var->bits_per_pixel,
              var->xres_virtual, var->yres_virtual,
              fb->width, fb->height, fb->bits_per_pixel);
        return -EINVAL;
    }

    switch (var->bits_per_pixel) {
    case 16:
        depth = (var->green.length == 6) ? 16 : 15;
        break;
    case 32:
        depth = (var->transp.length > 0) ? 32 : 24;
        break;
    default:
        depth = var->bits_per_pixel;
        break;
    }

    switch (depth) {
    case 8:
        var->red.offset = 0;
        var->green.offset = 0;
        var->blue.offset = 0;
        var->red.length = 8;
        var->green.length = 8;
        var->blue.length = 8;
        var->transp.length = 0;
        var->transp.offset = 0;
        break;
    case 15:
        var->red.offset = 10;
        var->green.offset = 5;
        var->blue.offset = 0;
        var->red.length = 5;
        var->green.length = 5;
        var->blue.length = 5;
        var->transp.length = 1;
        var->transp.offset = 15;
        break;
    case 16:
        var->red.offset = 11;
        var->green.offset = 5;
        var->blue.offset = 0;
        var->red.length = 5;
        var->green.length = 6;
        var->blue.length = 5;
        var->transp.length = 0;
        var->transp.offset = 0;
        break;
    case 24:
        var->red.offset = 16;
        var->green.offset = 8;
        var->blue.offset = 0;
        var->red.length = 8;
        var->green.length = 8;
        var->blue.length = 8;
        var->transp.length = 0;
        var->transp.offset = 0;
        break;
    case 32:
        var->red.offset = 16;
        var->green.offset = 8;
        var->blue.offset = 0;
        var->red.length = 8;
        var->green.length = 8;
        var->blue.length = 8;
        var->transp.length = 8;
        var->transp.offset = 24;
        break;
    default:
        return -EINVAL;
    }
    return 0;
}
EXPORT_SYMBOL(drm_fb_helper_check_var);

/* this will let fbcon do the mode init */
int drm_fb_helper_set_par(struct fb_info *info)
{
    struct drm_fb_helper *fb_helper = info->par;
    struct drm_device *dev = fb_helper->dev;
    struct fb_var_screeninfo *var = &info->var;
    struct drm_crtc *crtc;
    int ret;
    int i;

    if (var->pixclock != 0) {
        DRM_ERROR("PIXEL CLOCK SET\n");
        return -EINVAL;
    }

    mutex_lock(&dev->mode_config.mutex);
    for (i = 0; i < fb_helper->crtc_count; i++) {
        crtc = fb_helper->crtc_info[i].mode_set.crtc;
        ret = crtc->funcs->set_config(&fb_helper->crtc_info[i].mode_set);
        if (ret) {
            mutex_unlock(&dev->mode_config.mutex);
            return ret;
        }
    }
    mutex_unlock(&dev->mode_config.mutex);

    if (fb_helper->delayed_hotplug) {
        fb_helper->delayed_hotplug = false;
        drm_fb_helper_hotplug_event(fb_helper);
    }
    return 0;
}
EXPORT_SYMBOL(drm_fb_helper_set_par);

int drm_fb_helper_pan_display(struct fb_var_screeninfo *var,
                  struct fb_info *info)
{
    struct drm_fb_helper *fb_helper = info->par;
    struct drm_device *dev = fb_helper->dev;
    struct drm_mode_set *modeset;
    struct drm_crtc *crtc;
    int ret = 0;
    int i;

    mutex_lock(&dev->mode_config.mutex);
    for (i = 0; i < fb_helper->crtc_count; i++) {
        crtc = fb_helper->crtc_info[i].mode_set.crtc;

        modeset = &fb_helper->crtc_info[i].mode_set;

        modeset->x = var->xoffset;
        modeset->y = var->yoffset;

        if (modeset->num_connectors) {
            ret = crtc->funcs->set_config(modeset);
            if (!ret) {
                info->var.xoffset = var->xoffset;
                info->var.yoffset = var->yoffset;
            }
        }
    }
    mutex_unlock(&dev->mode_config.mutex);
    return ret;
}
EXPORT_SYMBOL(drm_fb_helper_pan_display);

int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper,
                  int preferred_bpp)
{
    int new_fb = 0;
    int crtc_count = 0;
    int i;
    struct fb_info *info;
    struct drm_fb_helper_surface_size sizes;
    int gamma_size = 0;

    memset(&sizes, 0, sizeof(struct drm_fb_helper_surface_size));
    sizes.surface_depth = 24;
    sizes.surface_bpp = 32;
    sizes.fb_width = (unsigned)-1;
    sizes.fb_height = (unsigned)-1;

    /* if driver picks 8 or 16 by default use that
       for both depth/bpp */
    if (preferred_bpp != sizes.surface_bpp) {
        sizes.surface_depth = sizes.surface_bpp = preferred_bpp;
    }
    /* first up get a count of crtcs now in use and new min/maxes width/heights */
    for (i = 0; i < fb_helper->connector_count; i++) {
        struct drm_fb_helper_connector *fb_helper_conn = fb_helper->connector_info[i];
        struct drm_cmdline_mode *cmdline_mode;

        cmdline_mode = &fb_helper_conn->cmdline_mode;

        if (cmdline_mode->bpp_specified) {
            switch (cmdline_mode->bpp) {
            case 8:
                sizes.surface_depth = sizes.surface_bpp = 8;
                break;
            case 15:
                sizes.surface_depth = 15;
                sizes.surface_bpp = 16;
                break;
            case 16:
                sizes.surface_depth = sizes.surface_bpp = 16;
                break;
            case 24:
                sizes.surface_depth = sizes.surface_bpp = 24;
                break;
            case 32:
                sizes.surface_depth = 24;
                sizes.surface_bpp = 32;
                break;
            }
            break;
        }
    }

    crtc_count = 0;
    for (i = 0; i < fb_helper->crtc_count; i++) {
        struct drm_display_mode *desired_mode;
        desired_mode = fb_helper->crtc_info[i].desired_mode;

        if (desired_mode) {
            if (gamma_size == 0)
                gamma_size = fb_helper->crtc_info[i].mode_set.crtc->gamma_size;
            if (desired_mode->hdisplay < sizes.fb_width)
                sizes.fb_width = desired_mode->hdisplay;
            if (desired_mode->vdisplay < sizes.fb_height)
                sizes.fb_height = desired_mode->vdisplay;
            if (desired_mode->hdisplay > sizes.surface_width)
                sizes.surface_width = desired_mode->hdisplay;
            if (desired_mode->vdisplay > sizes.surface_height)
                sizes.surface_height = desired_mode->vdisplay;
            crtc_count++;
        }
    }

    if (crtc_count == 0 || sizes.fb_width == -1 || sizes.fb_height == -1) {
        /* hmm everyone went away - assume VGA cable just fell out
           and will come back later. */
        DRM_INFO("Cannot find any crtc or sizes - going 1024x768\n");
        sizes.fb_width = sizes.surface_width = 1024;
        sizes.fb_height = sizes.surface_height = 768;
    }

    /* push down into drivers */
    new_fb = (*fb_helper->funcs->fb_probe)(fb_helper, &sizes);
    if (new_fb < 0)
        return new_fb;

    info = fb_helper->fbdev;

    /* set the fb pointer */
    for (i = 0; i < fb_helper->crtc_count; i++) {
        fb_helper->crtc_info[i].mode_set.fb = fb_helper->fb;
    }

    if (new_fb) {
        info->var.pixclock = 0;
        if (register_framebuffer(info) < 0) {
            return -EINVAL;
        }

        printk(KERN_INFO "fb%d: %s frame buffer device\n", info->node,
               info->fix.id);

    } else {
        drm_fb_helper_set_par(info);
    }

    /* Switch back to kernel console on panic */
    /* multi card linked list maybe */
    if (list_empty(&kernel_fb_helper_list)) {
        printk(KERN_INFO "drm: registered panic notifier\n");
        atomic_notifier_chain_register(&panic_notifier_list,
                           &paniced);
        register_sysrq_key('v', &sysrq_drm_fb_helper_restore_op);
    }
    if (new_fb)
        list_add(&fb_helper->kernel_fb_list, &kernel_fb_helper_list);

    return 0;
}
EXPORT_SYMBOL(drm_fb_helper_single_fb_probe);

void drm_fb_helper_fill_fix(struct fb_info *info, uint32_t pitch,
                uint32_t depth)
{
    info->fix.type = FB_TYPE_PACKED_PIXELS;
    info->fix.visual = depth == 8 ? FB_VISUAL_PSEUDOCOLOR :
        FB_VISUAL_TRUECOLOR;
    info->fix.mmio_start = 0;
    info->fix.mmio_len = 0;
    info->fix.type_aux = 0;
    info->fix.xpanstep = 1; /* doing it in hw */
    info->fix.ypanstep = 1; /* doing it in hw */
    info->fix.ywrapstep = 0;
    info->fix.accel = FB_ACCEL_NONE;
    info->fix.type_aux = 0;

    info->fix.line_length = pitch;
    return;
}
EXPORT_SYMBOL(drm_fb_helper_fill_fix);

void drm_fb_helper_fill_var(struct fb_info *info, struct drm_fb_helper *fb_helper,
                uint32_t fb_width, uint32_t fb_height)
{
    struct drm_framebuffer *fb = fb_helper->fb;
    info->pseudo_palette = fb_helper->pseudo_palette;
    info->var.xres_virtual = fb->width;
    info->var.yres_virtual = fb->height;
    info->var.bits_per_pixel = fb->bits_per_pixel;
    info->var.accel_flags = FB_ACCELF_TEXT;
    info->var.xoffset = 0;
    info->var.yoffset = 0;
    info->var.activate = FB_ACTIVATE_NOW;
    info->var.height = -1;
    info->var.width = -1;

    switch (fb->depth) {
    case 8:
        info->var.red.offset = 0;
        info->var.green.offset = 0;
        info->var.blue.offset = 0;
        info->var.red.length = 8; /* 8bit DAC */
        info->var.green.length = 8;
        info->var.blue.length = 8;
        info->var.transp.offset = 0;
        info->var.transp.length = 0;
        break;
    case 15:
        info->var.red.offset = 10;
        info->var.green.offset = 5;
        info->var.blue.offset = 0;
        info->var.red.length = 5;
        info->var.green.length = 5;
        info->var.blue.length = 5;
        info->var.transp.offset = 15;
        info->var.transp.length = 1;
        break;
    case 16:
        info->var.red.offset = 11;
        info->var.green.offset = 5;
        info->var.blue.offset = 0;
        info->var.red.length = 5;
        info->var.green.length = 6;
        info->var.blue.length = 5;
        info->var.transp.offset = 0;
        break;
    case 24:
        info->var.red.offset = 16;
        info->var.green.offset = 8;
        info->var.blue.offset = 0;
        info->var.red.length = 8;
        info->var.green.length = 8;
        info->var.blue.length = 8;
        info->var.transp.offset = 0;
        info->var.transp.length = 0;
        break;
    case 32:
        info->var.red.offset = 16;
        info->var.green.offset = 8;
        info->var.blue.offset = 0;
        info->var.red.length = 8;
        info->var.green.length = 8;
        info->var.blue.length = 8;
        info->var.transp.offset = 24;
        info->var.transp.length = 8;
        break;
    default:
        break;
    }

    info->var.xres = fb_width;
    info->var.yres = fb_height;
}
EXPORT_SYMBOL(drm_fb_helper_fill_var);

static int drm_fb_helper_probe_connector_modes(struct drm_fb_helper *fb_helper,
                           uint32_t maxX,
                           uint32_t maxY)
{
    struct drm_connector *connector;
    int count = 0;
    int i;

    for (i = 0; i < fb_helper->connector_count; i++) {
        connector = fb_helper->connector_info[i]->connector;
        count += connector->funcs->fill_modes(connector, maxX, maxY);
    }

    return count;
}

static struct drm_display_mode *drm_has_preferred_mode(struct drm_fb_helper_connector *fb_connector, int width, int height)
{
    struct drm_display_mode *mode;

    list_for_each_entry(mode, &fb_connector->connector->modes, head) {
        if (drm_mode_width(mode) > width ||
            drm_mode_height(mode) > height)
            continue;
        if (mode->type & DRM_MODE_TYPE_PREFERRED)
            return mode;
    }
    return NULL;
}

static bool drm_has_cmdline_mode(struct drm_fb_helper_connector *fb_connector)
{
    struct drm_cmdline_mode *cmdline_mode;
    cmdline_mode = &fb_connector->cmdline_mode;
    return cmdline_mode->specified;
}

static struct drm_display_mode *drm_pick_cmdline_mode(struct drm_fb_helper_connector *fb_helper_conn,
                              int width, int height)
{
    struct drm_cmdline_mode *cmdline_mode;
    struct drm_display_mode *mode = NULL;

    cmdline_mode = &fb_helper_conn->cmdline_mode;
    if (cmdline_mode->specified == false)
        return mode;

    /* 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;

    list_for_each_entry(mode, &fb_helper_conn->connector->modes, head) {
        /* check width/height */
        if (mode->hdisplay != cmdline_mode->xres ||
            mode->vdisplay != cmdline_mode->yres)
            continue;

        if (cmdline_mode->refresh_specified) {
            if (mode->vrefresh != cmdline_mode->refresh)
                continue;
        }

        if (cmdline_mode->interlace) {
            if (!(mode->flags & DRM_MODE_FLAG_INTERLACE))
                continue;
        }
        return mode;
    }

create_mode:
    mode = drm_mode_create_from_cmdline_mode(fb_helper_conn->connector->dev,
                         cmdline_mode);
    list_add(&mode->head, &fb_helper_conn->connector->modes);
    return mode;
}

static bool drm_connector_enabled(struct drm_connector *connector, bool strict)
{
    bool enable;

    if (strict) {
        enable = connector->status == connector_status_connected;
    } else {
        enable = connector->status != connector_status_disconnected;
    }
    return enable;
}

static void drm_enable_connectors(struct drm_fb_helper *fb_helper,
                  bool *enabled)
{
    bool any_enabled = false;
    struct drm_connector *connector;
    int i = 0;

    for (i = 0; i < fb_helper->connector_count; i++) {
        connector = fb_helper->connector_info[i]->connector;
        enabled[i] = drm_connector_enabled(connector, true);
        DRM_DEBUG_KMS("connector %d enabled? %s\n", connector->base.id,
              enabled[i] ? "yes" : "no");
        any_enabled |= enabled[i];
    }

    if (any_enabled)
        return;

    for (i = 0; i < fb_helper->connector_count; i++) {
        connector = fb_helper->connector_info[i]->connector;
        enabled[i] = drm_connector_enabled(connector, false);
    }
}

static bool drm_target_cloned(struct drm_fb_helper *fb_helper,
                  struct drm_display_mode **modes,
                  bool *enabled, int width, int height)
{
    int count, i, j;
    bool can_clone = false;
    struct drm_fb_helper_connector *fb_helper_conn;
    struct drm_display_mode *dmt_mode, *mode;

    /* only contemplate cloning in the single crtc case */
    if (fb_helper->crtc_count > 1)
        return false;

    count = 0;
    for (i = 0; i < fb_helper->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 < fb_helper->connector_count; i++) {
        if (!enabled[i])
            continue;
        fb_helper_conn = fb_helper->connector_info[i];
        modes[i] = drm_pick_cmdline_mode(fb_helper_conn, width, height);
        if (!modes[i]) {
            can_clone = false;
            break;
        }
        for (j = 0; j < i; j++) {
            if (!enabled[j])
                continue;
            if (!drm_mode_equal(modes[j], modes[i]))
                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(fb_helper->dev, 1024, 768, 60, false);

    for (i = 0; i < fb_helper->connector_count; i++) {

        if (!enabled[i])
            continue;

        fb_helper_conn = fb_helper->connector_info[i];
        list_for_each_entry(mode, &fb_helper_conn->connector->modes, head) {
            if (drm_mode_equal(mode, dmt_mode))
                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 bool drm_target_preferred(struct drm_fb_helper *fb_helper,
                 struct drm_display_mode **modes,
                 bool *enabled, int width, int height)
{
    struct drm_fb_helper_connector *fb_helper_conn;
    int i;

    for (i = 0; i < fb_helper->connector_count; i++) {
        fb_helper_conn = fb_helper->connector_info[i];

        if (enabled[i] == false)
            continue;

        DRM_DEBUG_KMS("looking for cmdline mode on connector %d\n",
                  fb_helper_conn->connector->base.id);

        /* got for command line mode first */
        modes[i] = drm_pick_cmdline_mode(fb_helper_conn, width, height);
        if (!modes[i]) {
            DRM_DEBUG_KMS("looking for preferred mode on connector %d\n",
                      fb_helper_conn->connector->base.id);
            modes[i] = drm_has_preferred_mode(fb_helper_conn, width, height);
        }
        /* No preferred modes, pick one off the list */
        if (!modes[i] && !list_empty(&fb_helper_conn->connector->modes)) {
            list_for_each_entry(modes[i], &fb_helper_conn->connector->modes, head)
                break;
        }
        DRM_DEBUG_KMS("found mode %s\n", modes[i] ? modes[i]->name :
              "none");
    }
    return true;
}

static int drm_pick_crtcs(struct drm_fb_helper *fb_helper,
              struct drm_fb_helper_crtc **best_crtcs,
              struct drm_display_mode **modes,
              int n, int width, int height)
{
    int c, o;
    struct drm_device *dev = fb_helper->dev;
    struct drm_connector *connector;
    struct drm_connector_helper_funcs *connector_funcs;
    struct drm_encoder *encoder;
    struct drm_fb_helper_crtc *best_crtc;
    int my_score, best_score, score;
    struct drm_fb_helper_crtc **crtcs, *crtc;
    struct drm_fb_helper_connector *fb_helper_conn;

    if (n == fb_helper->connector_count)
        return 0;

    fb_helper_conn = fb_helper->connector_info[n];
    connector = fb_helper_conn->connector;

    best_crtcs[n] = NULL;
    best_crtc = NULL;
    best_score = drm_pick_crtcs(fb_helper, best_crtcs, modes, n+1, width, height);
    if (modes[n] == NULL)
        return best_score;

    crtcs = kzalloc(dev->mode_config.num_connector *
            sizeof(struct drm_fb_helper_crtc *), GFP_KERNEL);
    if (!crtcs)
        return best_score;

    my_score = 1;
    if (connector->status == connector_status_connected)
        my_score++;
    if (drm_has_cmdline_mode(fb_helper_conn))
        my_score++;
    if (drm_has_preferred_mode(fb_helper_conn, width, height))
        my_score++;

    connector_funcs = connector->helper_private;
    encoder = connector_funcs->best_encoder(connector);
    if (!encoder)
        goto out;

    /* select a crtc for this connector and then attempt to configure
       remaining connectors */
    for (c = 0; c < fb_helper->crtc_count; c++) {
        crtc = &fb_helper->crtc_info[c];

        if ((encoder->possible_crtcs & (1 << c)) == 0) {
            continue;
        }

        for (o = 0; o < n; o++)
            if (best_crtcs[o] == crtc)
                break;

        if (o < n) {
            /* ignore cloning unless only a single crtc */
            if (fb_helper->crtc_count > 1)
                continue;

            if (!drm_mode_equal(modes[o], modes[n]))
                continue;
        }

        crtcs[n] = crtc;
        memcpy(crtcs, best_crtcs, n * sizeof(struct drm_fb_helper_crtc *));
        score = my_score + drm_pick_crtcs(fb_helper, crtcs, modes, n + 1,
                          width, height);
        if (score > best_score) {
            best_crtc = crtc;
            best_score = score;
            memcpy(best_crtcs, crtcs,
                   dev->mode_config.num_connector *
                   sizeof(struct drm_fb_helper_crtc *));
        }
    }
out:
    kfree(crtcs);
    return best_score;
}

static void drm_setup_crtcs(struct drm_fb_helper *fb_helper)
{
    struct drm_device *dev = fb_helper->dev;
    struct drm_fb_helper_crtc **crtcs;
    struct drm_display_mode **modes;
    struct drm_mode_set *modeset;
    bool *enabled;
    int width, height;
    int i, ret;

    DRM_DEBUG_KMS("\n");

    width = dev->mode_config.max_width;
    height = dev->mode_config.max_height;

    crtcs = kcalloc(dev->mode_config.num_connector,
            sizeof(struct drm_fb_helper_crtc *), GFP_KERNEL);
    modes = kcalloc(dev->mode_config.num_connector,
            sizeof(struct drm_display_mode *), GFP_KERNEL);
    enabled = kcalloc(dev->mode_config.num_connector,
              sizeof(bool), GFP_KERNEL);

    drm_enable_connectors(fb_helper, enabled);

    ret = drm_target_cloned(fb_helper, modes, enabled, width, height);
    if (!ret) {
        ret = drm_target_preferred(fb_helper, modes, enabled, width, height);
        if (!ret)
            DRM_ERROR("Unable to find initial modes\n");
    }

    DRM_DEBUG_KMS("picking CRTCs for %dx%d config\n", width, height);

    drm_pick_crtcs(fb_helper, crtcs, modes, 0, width, height);

    /* need to set the modesets up here for use later */
    /* fill out the connector<->crtc mappings into the modesets */
    for (i = 0; i < fb_helper->crtc_count; i++) {
        modeset = &fb_helper->crtc_info[i].mode_set;
        modeset->num_connectors = 0;
    }

    for (i = 0; i < fb_helper->connector_count; i++) {
        struct drm_display_mode *mode = modes[i];
        struct drm_fb_helper_crtc *fb_crtc = crtcs[i];
        modeset = &fb_crtc->mode_set;

        if (mode && fb_crtc) {
            DRM_DEBUG_KMS("desired mode %s set on crtc %d\n",
                      mode->name, fb_crtc->mode_set.crtc->base.id);
            fb_crtc->desired_mode = mode;
            if (modeset->mode)
                drm_mode_destroy(dev, modeset->mode);
            modeset->mode = drm_mode_duplicate(dev,
                               fb_crtc->desired_mode);
            modeset->connectors[modeset->num_connectors++] = fb_helper->connector_info[i]->connector;
        }
    }

    kfree(crtcs);
    kfree(modes);
    kfree(enabled);
}

bool drm_fb_helper_initial_config(struct drm_fb_helper *fb_helper, int bpp_sel)
{
    struct drm_device *dev = fb_helper->dev;
    int count = 0;

    /* disable all the possible outputs/crtcs before entering KMS mode */
    drm_helper_disable_unused_functions(fb_helper->dev);

    drm_fb_helper_parse_command_line(fb_helper);

    count = drm_fb_helper_probe_connector_modes(fb_helper,
                            dev->mode_config.max_width,
                            dev->mode_config.max_height);
    /*
     * we shouldn't end up with no modes here.
     */
    if (count == 0) {
        printk(KERN_INFO "No connectors reported connected with modes\n");
    }
    drm_setup_crtcs(fb_helper);

    return drm_fb_helper_single_fb_probe(fb_helper, bpp_sel);
}
EXPORT_SYMBOL(drm_fb_helper_initial_config);

int drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper)
{
    struct drm_device *dev = fb_helper->dev;
    int count = 0;
    u32 max_width, max_height, bpp_sel;
    int bound = 0, crtcs_bound = 0;
    struct drm_crtc *crtc;

    if (!fb_helper->fb)
        return 0;

    mutex_lock(&dev->mode_config.mutex);
    list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
        if (crtc->fb)
            crtcs_bound++;
        if (crtc->fb == fb_helper->fb)
            bound++;
    }

    if (bound < crtcs_bound) {
        fb_helper->delayed_hotplug = true;
        mutex_unlock(&dev->mode_config.mutex);
        return 0;
    }
    DRM_DEBUG_KMS("\n");

    max_width = fb_helper->fb->width;
    max_height = fb_helper->fb->height;
    bpp_sel = fb_helper->fb->bits_per_pixel;

    count = drm_fb_helper_probe_connector_modes(fb_helper, max_width,
                            max_height);
    drm_setup_crtcs(fb_helper);
    mutex_unlock(&dev->mode_config.mutex);

    return drm_fb_helper_single_fb_probe(fb_helper, bpp_sel);
}
EXPORT_SYMBOL(drm_fb_helper_hotplug_event);

/* The Kconfig DRM_KMS_HELPER selects FRAMEBUFFER_CONSOLE (if !EXPERT)
 * but the module doesn't depend on any fb console symbols.  At least
 * attempt to load fbcon to avoid leaving the system without a usable console.
 */
#if defined(CONFIG_FRAMEBUFFER_CONSOLE_MODULE) && !defined(CONFIG_EXPERT)
static int __init drm_fb_helper_modinit(void)
{
    const char *name = "fbcon";
    struct module *fbcon;

    mutex_lock(&module_mutex);
    fbcon = find_module(name);
    mutex_unlock(&module_mutex);

    if (!fbcon)
        request_module_nowait(name);
    return 0;
}

module_init(drm_fb_helper_modinit);
#endif