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32 results

virtio_pci_common.c

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  • drm_fb_helper.c 37.53 KiB
    /*
     * Copyright (c) 2006-2009 Red Hat Inc.
     * Copyright (c) 2006-2008 Intel Corporation
     * Copyright (c) 2007 Dave Airlie <airlied@linux.ie>
     *
     * 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 <airlied@linux.ie>
     *      Jesse Barnes <jesse.barnes@intel.com>
     */
    #include <linux/kernel.h>
    #include <linux/sysrq.h>
    #include <linux/slab.h>
    #include <linux/fb.h>
    #include "drmP.h"
    #include "drm_crtc.h"
    #include "drm_fb_helper.h"
    #include "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);
    
    /**
     * drm_fb_helper_connector_parse_command_line - parse command line for connector
     * @connector - connector to parse line for
     * @mode_option - per connector mode option
     *
     * This parses the connector specific then generic command lines for
     * modes and options to configure the connector.
     *
     * This uses the same parameters as the fb modedb.c, except for extra
     *	<xres>x<yres>[M][R][-<bpp>][@<refresh>][i][m][eDd]
     *
     * enable/enable Digital/disable bit at the end
     */
    static bool drm_fb_helper_connector_parse_command_line(struct drm_fb_helper_connector *fb_helper_conn,
    						       const char *mode_option)
    {
    	const char *name;
    	unsigned int namelen;
    	int res_specified = 0, bpp_specified = 0, refresh_specified = 0;
    	unsigned int xres = 0, yres = 0, bpp = 32, refresh = 0;
    	int yres_specified = 0, cvt = 0, rb = 0, interlace = 0, margins = 0;
    	int i;
    	enum drm_connector_force force = DRM_FORCE_UNSPECIFIED;
    	struct drm_fb_helper_cmdline_mode *cmdline_mode;
    	struct drm_connector *connector = fb_helper_conn->connector;
    
    	if (!fb_helper_conn)
    		return false;
    
    	cmdline_mode = &fb_helper_conn->cmdline_mode;
    	if (!mode_option)
    		mode_option = fb_mode_option;
    
    	if (!mode_option) {
    		cmdline_mode->specified = false;
    		return false;
    	}
    
    	name = mode_option;
    	namelen = strlen(name);
    	for (i = namelen-1; i >= 0; i--) {
    		switch (name[i]) {
    		case '@':
    			namelen = i;
    			if (!refresh_specified && !bpp_specified &&
    			    !yres_specified) {
    				refresh = simple_strtol(&name[i+1], NULL, 10);
    				refresh_specified = 1;
    				if (cvt || rb)
    					cvt = 0;
    			} else
    				goto done;
    			break;
    		case '-':
    			namelen = i;
    			if (!bpp_specified && !yres_specified) {
    				bpp = simple_strtol(&name[i+1], NULL, 10);
    				bpp_specified = 1;
    				if (cvt || rb)
    					cvt = 0;
    			} else
    				goto done;
    			break;
    		case 'x':
    			if (!yres_specified) {
    				yres = simple_strtol(&name[i+1], NULL, 10);
    				yres_specified = 1;
    			} else
    				goto done;
    		case '0' ... '9':
    			break;
    		case 'M':
    			if (!yres_specified)
    				cvt = 1;
    			break;
    		case 'R':
    			if (cvt)
    				rb = 1;
    			break;
    		case 'm':
    			if (!cvt)
    				margins = 1;
    			break;
    		case 'i':
    			if (!cvt)
    				interlace = 1;
    			break;
    		case 'e':
    			force = DRM_FORCE_ON;
    			break;
    		case 'D':
    			if ((connector->connector_type != DRM_MODE_CONNECTOR_DVII) &&
    			    (connector->connector_type != DRM_MODE_CONNECTOR_HDMIB))
    				force = DRM_FORCE_ON;
    			else
    				force = DRM_FORCE_ON_DIGITAL;
    			break;
    		case 'd':
    			force = DRM_FORCE_OFF;
    			break;
    		default:
    			goto done;
    		}
    	}
    	if (i < 0 && yres_specified) {
    		xres = simple_strtol(name, NULL, 10);
    		res_specified = 1;
    	}
    done:
    
    	DRM_DEBUG_KMS("cmdline mode for connector %s %dx%d@%dHz%s%s%s\n",
    		drm_get_connector_name(connector), xres, yres,
    		(refresh) ? refresh : 60, (rb) ? " reduced blanking" :
    		"", (margins) ? " with margins" : "", (interlace) ?
    		" interlaced" : "");
    
    	if (force) {
    		const char *s;
    		switch (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 = force;
    	}
    
    	if (res_specified) {
    		cmdline_mode->specified = true;
    		cmdline_mode->xres = xres;
    		cmdline_mode->yres = yres;
    	}
    
    	if (refresh_specified) {
    		cmdline_mode->refresh_specified = true;
    		cmdline_mode->refresh = refresh;
    	}
    
    	if (bpp_specified) {
    		cmdline_mode->bpp_specified = true;
    		cmdline_mode->bpp = bpp;
    	}
    	cmdline_mode->rb = rb ? true : false;
    	cmdline_mode->cvt = cvt  ? true : false;
    	cmdline_mode->interlace = interlace ? true : false;
    
    	return true;
    }
    
    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++) {
    		char *option = NULL;
    
    		fb_helper_conn = fb_helper->connector_info[i];
    
    		/* do something on return - turn off connector maybe */
    		if (fb_get_options(drm_get_connector_name(fb_helper_conn->connector), &option))
    			continue;
    
    		drm_fb_helper_connector_parse_command_line(fb_helper_conn, option);
    	}
    	return 0;
    }
    
    bool drm_fb_helper_force_kernel_mode(void)
    {
    	int i = 0;
    	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) {
    		for (i = 0; i < helper->crtc_count; i++) {
    			struct drm_mode_set *mode_set = &helper->crtc_info[i].mode_set;
    			ret = drm_crtc_helper_set_config(mode_set);
    			if (ret)
    				error = true;
    		}
    	}
    	return error;
    }
    
    int drm_fb_helper_panic(struct notifier_block *n, unsigned long ununsed,
    			void *panic_str)
    {
    	printk(KERN_ERR "panic occurred, switching back to text console\n");
    	return drm_fb_helper_force_kernel_mode();
    	return 0;
    }
    EXPORT_SYMBOL(drm_fb_helper_panic);
    
    static struct notifier_block paniced = {
    	.notifier_call = drm_fb_helper_panic,
    };
    
    /**
     * drm_fb_helper_restore - restore the framebuffer console (kernel) config
     *
     * Restore's the kernel's fbcon mode, used for lastclose & panic paths.
     */
    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, struct tty_struct *dummy3)
    {
    	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_on(struct fb_info *info)
    {
    	struct drm_fb_helper *fb_helper = info->par;
    	struct drm_device *dev = fb_helper->dev;
    	struct drm_crtc *crtc;
    	struct drm_crtc_helper_funcs *crtc_funcs;
    	struct drm_connector *connector;
    	struct drm_encoder *encoder;
    	int i, j;
    
    	/*
    	 * For each CRTC in this fb, turn the crtc on then,
    	 * find all associated encoders and turn them on.
    	 */
    	mutex_lock(&dev->mode_config.mutex);
    	for (i = 0; i < fb_helper->crtc_count; i++) {
    		crtc = fb_helper->crtc_info[i].mode_set.crtc;
    		crtc_funcs = crtc->helper_private;
    
    		if (!crtc->enabled)
    			continue;
    
    		crtc_funcs->dpms(crtc, DRM_MODE_DPMS_ON);
    
    		/* Walk the connectors & encoders on this fb turning them on */
    		for (j = 0; j < fb_helper->connector_count; j++) {
    			connector = fb_helper->connector_info[j]->connector;
    			connector->dpms = DRM_MODE_DPMS_ON;
    			drm_connector_property_set_value(connector,
    							 dev->mode_config.dpms_property,
    							 DRM_MODE_DPMS_ON);
    		}
    		/* Found a CRTC on this fb, now find encoders */
    		list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
    			if (encoder->crtc == crtc) {
    				struct drm_encoder_helper_funcs *encoder_funcs;
    
    				encoder_funcs = encoder->helper_private;
    				encoder_funcs->dpms(encoder, DRM_MODE_DPMS_ON);
    			}
    		}
    	}
    	mutex_unlock(&dev->mode_config.mutex);
    }
    
    static void drm_fb_helper_off(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_crtc_helper_funcs *crtc_funcs;
    	struct drm_connector *connector;
    	struct drm_encoder *encoder;
    	int i, j;
    
    	/*
    	 * For each CRTC in this fb, find all associated encoders
    	 * and turn them off, then turn off the CRTC.
    	 */
    	mutex_lock(&dev->mode_config.mutex);
    	for (i = 0; i < fb_helper->crtc_count; i++) {
    		crtc = fb_helper->crtc_info[i].mode_set.crtc;
    		crtc_funcs = crtc->helper_private;
    
    		if (!crtc->enabled)
    			continue;
    
    		/* Walk the connectors on this fb and mark them off */
    		for (j = 0; j < fb_helper->connector_count; j++) {
    			connector = fb_helper->connector_info[j]->connector;
    			connector->dpms = dpms_mode;
    			drm_connector_property_set_value(connector,
    							 dev->mode_config.dpms_property,
    							 dpms_mode);
    		}
    		/* Found a CRTC on this fb, now find encoders */
    		list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
    			if (encoder->crtc == crtc) {
    				struct drm_encoder_helper_funcs *encoder_funcs;
    
    				encoder_funcs = encoder->helper_private;
    				encoder_funcs->dpms(encoder, dpms_mode);
    			}
    		}
    		crtc_funcs->dpms(crtc, DRM_MODE_DPMS_OFF);
    	}
    	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_on(info);
    		break;
    	/* Display: Off; HSync: On, VSync: On */
    	case FB_BLANK_NORMAL:
    		drm_fb_helper_off(info, DRM_MODE_DPMS_STANDBY);
    		break;
    	/* Display: Off; HSync: Off, VSync: On */
    	case FB_BLANK_HSYNC_SUSPEND:
    		drm_fb_helper_off(info, DRM_MODE_DPMS_STANDBY);
    		break;
    	/* Display: Off; HSync: On, VSync: Off */
    	case FB_BLANK_VSYNC_SUSPEND:
    		drm_fb_helper_off(info, DRM_MODE_DPMS_SUSPEND);
    		break;
    	/* Display: Off; HSync: Off, VSync: Off */
    	case FB_BLANK_POWERDOWN:
    		drm_fb_helper_off(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);
    	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 ret = 0;
    	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) {
    			ret = -ENOMEM;
    			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].crtc_id = crtc->base.id;
    		fb_helper->crtc_info[i].mode_set.crtc = crtc;
    		i++;
    	}
    	fb_helper->conn_limit = max_conn_count;
    	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);
    		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, 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 (i = 0; i < cmap->len; i++) {
    			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)
    		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) {
    		DRM_DEBUG("fb userspace requested width/height/bpp is greater than current fb "
    			  "object %dx%d-%d > %dx%d-%d\n", var->xres, var->yres, var->bits_per_pixel,
    			  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_fb_helper_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.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.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_fb_helper_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_fb_helper_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:
    	if (cmdline_mode->cvt)
    		mode = drm_cvt_mode(fb_helper_conn->connector->dev,
    				    cmdline_mode->xres, cmdline_mode->yres,
    				    cmdline_mode->refresh_specified ? cmdline_mode->refresh : 60,
    				    cmdline_mode->rb, cmdline_mode->interlace,
    				    cmdline_mode->margins);
    	else
    		mode = drm_gtf_mode(fb_helper_conn->connector->dev,
    				    cmdline_mode->xres, cmdline_mode->yres,
    				    cmdline_mode->refresh_specified ? cmdline_mode->refresh : 60,
    				    cmdline_mode->interlace,
    				    cmdline_mode->margins);
    	drm_mode_set_crtcinfo(mode, CRTC_INTERLACE_HALVE_V);
    	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);
    
    	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_encoder *encoder;
    	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;
    
    	/* clean out all the encoder/crtc combos */
    	list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
    		encoder->crtc = NULL;
    	}
    
    	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);
    }
    
    /**
     * drm_helper_initial_config - setup a sane initial connector configuration
     * @dev: DRM device
     *
     * LOCKING:
     * Called at init time, must take mode config lock.
     *
     * Scan the CRTCs and connectors and try to put together an initial setup.
     * At the moment, this is a cloned configuration across all heads with
     * a new framebuffer object as the backing store.
     *
     * RETURNS:
     * Zero if everything went ok, nonzero otherwise.
     */
    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);
    
    bool drm_fb_helper_hotplug_event(struct drm_fb_helper *fb_helper)
    {
    	int count = 0;
    	u32 max_width, max_height, bpp_sel;
    	bool bound = false, crtcs_bound = false;
    	struct drm_crtc *crtc;
    
    	if (!fb_helper->fb)
    		return false;
    
    	list_for_each_entry(crtc, &fb_helper->dev->mode_config.crtc_list, head) {
    		if (crtc->fb)
    			crtcs_bound = true;
    		if (crtc->fb == fb_helper->fb)
    			bound = true;
    	}
    
    	if (!bound && crtcs_bound) {
    		fb_helper->delayed_hotplug = true;
    		return false;
    	}
    	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);
    
    	return drm_fb_helper_single_fb_probe(fb_helper, bpp_sel);
    }
    EXPORT_SYMBOL(drm_fb_helper_hotplug_event);