text: /*
   * 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>
   */
  #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
  
  #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);
  
  /**
   * DOC: fbdev helpers
   *
   * The fb helper functions are useful to provide an fbdev on top of a drm kernel
   * mode setting driver. They can be used mostly independantely from the crtc
   * helper functions used by many drivers to implement the kernel mode setting
   * interfaces.
   *
   * Initialization is done as a three-step process with drm_fb_helper_init(),
   * drm_fb_helper_single_add_all_connectors() and drm_fb_helper_initial_config().
   * Drivers with fancier requirements than the default beheviour can override the
   * second step with their own code.  Teardown is done with drm_fb_helper_fini().
   *
   * At runtime drivers should restore the fbdev console by calling
   * drm_fb_helper_restore_fbdev_mode() from their ->lastclose callback. They
   * should also notify the fb helper code from updates to the output
   * configuration by calling drm_fb_helper_hotplug_event(). For easier
   * integration with the output polling code in drm_crtc_helper.c the modeset
   * code proves a ->output_poll_changed callback.
   *
   * All other functions exported by the fb helper library can be used to
   * implement the fbdev driver interface by the driver.
   */
  
  /**
   * drm_fb_helper_single_add_all_connectors() - add all connectors to fbdev
   * 					       emulation helper
   * @fb_helper: fbdev initialized with drm_fb_helper_init
   *
   * This functions adds all the available connectors for use with the given
   * fb_helper. This is a separate step to allow drivers to freely assign
   * connectors to the fbdev, e.g. if some are reserved for special purposes or
   * not adequate to be used for the fbcon.
   *
   * Since this is part of the initial setup before the fbdev is published, no
   * locking is required.
   */
  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);
  }
  
  /**
   * drm_fb_helper_debug_enter - implementation for ->fb_debug_enter
   * @info: fbdev registered by the helper
   */
  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;
  }
  
  /**
   * drm_fb_helper_debug_leave - implementation for ->fb_debug_leave
   * @info: fbdev registered by the helper
   */
  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);
  
  /**
   * drm_fb_helper_restore_fbdev_mode - restore fbdev configuration
   * @fb_helper: fbcon to restore
   *
   * This should be called from driver's drm ->lastclose callback
   * when implementing an fbcon on top of kms using this helper. This ensures that
   * the user isn't greeted with a black screen when e.g. X dies.
   */
  bool drm_fb_helper_restore_fbdev_mode(struct drm_fb_helper *fb_helper)
  {
  	bool error = false;
  	int i, ret;
  
  	drm_warn_on_modeset_not_all_locked(fb_helper->dev);
  
  	for (i = 0; i < fb_helper->crtc_count; i++) {
  		struct drm_mode_set *mode_set = &fb_helper->crtc_info[i].mode_set;
  		ret = drm_mode_set_config_internal(mode_set);
  		if (ret)
  			error = true;
  	}
  	return error;
  }
  EXPORT_SYMBOL(drm_fb_helper_restore_fbdev_mode);
  
  /*
   * restore fbcon display for all kms driver's using this helper, used for sysrq
   * and panic handling.
   */
  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;
  }
  
  static 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;
  
  	pr_err("panic occurred, switching back to text console\n");
  	return drm_fb_helper_force_kernel_mode();
  }
  
  static struct notifier_block paniced = {
  	.notifier_call = drm_fb_helper_panic,
  };
  
  static bool drm_fb_helper_is_bound(struct drm_fb_helper *fb_helper)
  {
  	struct drm_device *dev = fb_helper->dev;
  	struct drm_crtc *crtc;
  	int bound = 0, crtcs_bound = 0;
  
  	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)
  		return false;
  	return true;
  }
  
  #ifdef CONFIG_MAGIC_SYSRQ
  static void drm_fb_helper_restore_work_fn(struct work_struct *ignored)
  {
  	bool ret;
  	ret = drm_fb_helper_force_kernel_mode();
  	if (ret == true)
  		DRM_ERROR("Failed to restore crtc configuration\n");
  }
  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;
  
  	/*
  	 * fbdev->blank can be called from irq context in case of a panic.
  	 * Since we already have our own special panic handler which will
  	 * restore the fbdev console mode completely, just bail out early.
  	 */
  	if (oops_in_progress)
  		return;
  
  	/*
  	 * For each CRTC in this fb, turn the connectors on/off.
  	 */
  	drm_modeset_lock_all(dev);
  	if (!drm_fb_helper_is_bound(fb_helper)) {
  		drm_modeset_unlock_all(dev);
  		return;
  	}
  
  	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_object_property_set_value(&connector->base,
  				dev->mode_config.dpms_property, dpms_mode);
  		}
  	}
  	drm_modeset_unlock_all(dev);
  }
  
  /**
   * drm_fb_helper_blank - implementation for ->fb_blank
   * @blank: desired blanking state
   * @info: fbdev registered by the helper
   */
  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);
  }
  
  /**
   * drm_fb_helper_init - initialize a drm_fb_helper structure
   * @dev: drm device
   * @fb_helper: driver-allocated fbdev helper structure to initialize
   * @crtc_count: maximum number of crtcs to support in this fbdev emulation
   * @max_conn_count: max connector count
   *
   * This allocates the structures for the fbdev helper with the given limits.
   * Note that this won't yet touch the hardware (through the driver interfaces)
   * nor register the fbdev. This is only done in drm_fb_helper_initial_config()
   * to allow driver writes more control over the exact init sequence.
   *
   * Drivers must set fb_helper->funcs before calling
   * drm_fb_helper_initial_config().
   *
   * RETURNS:
   * Zero if everything went ok, nonzero otherwise.
   */
  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)) {
  			pr_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;
  }
  
  /**
   * drm_fb_helper_setcmap - implementation for ->fb_setcmap
   * @cmap: cmap to set
   * @info: fbdev registered by the helper
   */
  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);
  
  /**
   * drm_fb_helper_check_var - implementation for ->fb_check_var
   * @var: screeninfo to check
   * @info: fbdev registered by the helper
   */
  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);
  
  /**
   * drm_fb_helper_set_par - implementation for ->fb_set_par
   * @info: fbdev registered by the helper
   *
   * This will let fbcon do the mode init and is called at initialization time by
   * the fbdev core when registering the driver, and later on through the hotplug
   * callback.
   */
  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;
  	int ret;
  	int i;
  
  	if (var->pixclock != 0) {
  		DRM_ERROR("PIXEL CLOCK SET\n");
  		return -EINVAL;
  	}
  
  	drm_modeset_lock_all(dev);
  	for (i = 0; i < fb_helper->crtc_count; i++) {
  		ret = drm_mode_set_config_internal(&fb_helper->crtc_info[i].mode_set);
  		if (ret) {
  			drm_modeset_unlock_all(dev);
  			return ret;
  		}
  	}
  	drm_modeset_unlock_all(dev);
  
  	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);
  
  /**
   * drm_fb_helper_pan_display - implementation for ->fb_pan_display
   * @var: updated screen information
   * @info: fbdev registered by the helper
   */
  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;
  
  	drm_modeset_lock_all(dev);
  	if (!drm_fb_helper_is_bound(fb_helper)) {
  		drm_modeset_unlock_all(dev);
  		return -EBUSY;
  	}
  
  	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 = drm_mode_set_config_internal(modeset);
  			if (!ret) {
  				info->var.xoffset = var->xoffset;
  				info->var.yoffset = var->yoffset;
  			}
  		}
  	}
  	drm_modeset_unlock_all(dev);
  	return ret;
  }
  EXPORT_SYMBOL(drm_fb_helper_pan_display);
  
  /*
   * Allocates the backing storage and sets up the fbdev info structure through
   * the ->fb_probe callback and then registers the fbdev and sets up the panic
   * notifier.
   */
  static int drm_fb_helper_single_fb_probe(struct drm_fb_helper *fb_helper,
  					 int preferred_bpp)
  {
  	int ret = 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 */
  	ret = (*fb_helper->funcs->fb_probe)(fb_helper, &sizes);
  	if (ret < 0)
  		return ret;
  
  	info = fb_helper->fbdev;
  
  	/*
  	 * Set the fb pointer - usually drm_setup_crtcs does this for hotplug
  	 * events, but at init time drm_setup_crtcs needs to be called before
  	 * the fb is allocated (since we need to figure out the desired size of
  	 * the fb before we can allocate it ...). Hence we need to fix things up
  	 * here again.
  	 */
  	for (i = 0; i < fb_helper->crtc_count; i++)
  		if (fb_helper->crtc_info[i].mode_set.num_connectors)
  			fb_helper->crtc_info[i].mode_set.fb = fb_helper->fb;
  
  
  	info->var.pixclock = 0;
  	if (register_framebuffer(info) < 0)
  		return -EINVAL;
  
  	dev_info(fb_helper->dev->dev, "fb%d: %s frame buffer device\n",
  			info->node, info->fix.id);
  
  	/* Switch back to kernel console on panic */
  	/* multi card linked list maybe */
  	if (list_empty(&kernel_fb_helper_list)) {
  		dev_info(fb_helper->dev->dev, "registered panic notifier\n");
  		atomic_notifier_chain_register(&panic_notifier_list,
  					       &paniced);
  		register_sysrq_key('v', &sysrq_drm_fb_helper_restore_op);
  	}
  
  	list_add(&fb_helper->kernel_fb_list, &kernel_fb_helper_list);
  
  	return 0;
  }
  
  /**
   * drm_fb_helper_fill_fix - initializes fixed fbdev information
   * @info: fbdev registered by the helper
   * @pitch: desired pitch
   * @depth: desired depth
   *
   * Helper to fill in the fixed fbdev information useful for a non-accelerated
   * fbdev emulations. Drivers which support acceleration methods which impose
   * additional constraints need to set up their own limits.
   *
   * Drivers should call this (or their equivalent setup code) from their
   * ->fb_probe callback.
   */
  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);
  
  /**
   * drm_fb_helper_fill_var - initalizes variable fbdev information
   * @info: fbdev instance to set up
   * @fb_helper: fb helper instance to use as template
   * @fb_width: desired fb width
   * @fb_height: desired fb height
   *
   * Sets up the variable fbdev metainformation from the given fb helper instance
   * and the drm framebuffer allocated in fb_helper->fb.
   *
   * Drivers should call this (or their equivalent setup code) from their
   * ->fb_probe callback after having allocated the fbdev backing
   * storage framebuffer.
   */
  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;
  
  	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);
  	if (!crtcs || !modes || !enabled) {
  		DRM_ERROR("Memory allocation failed\n");
  		goto out;
  	}
  
  
  	drm_enable_connectors(fb_helper, enabled);
  
  	if (!(fb_helper->funcs->initial_config &&
  	      fb_helper->funcs->initial_config(fb_helper, crtcs, modes,
  					       enabled, width, height))) {
  		memset(modes, 0, dev->mode_config.num_connector*sizeof(modes[0]));
  		memset(crtcs, 0, dev->mode_config.num_connector*sizeof(crtcs[0]));
  
  		if (!drm_target_cloned(fb_helper,
  				       modes, enabled, width, height) &&
  		    !drm_target_preferred(fb_helper,
  					  modes, enabled, width, height))
  			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;
  		modeset->fb = NULL;
  	}
  
  	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;
  			modeset->fb = fb_helper->fb;
  		}
  	}
  
  	/* Clear out any old modes if there are no more connected outputs. */
  	for (i = 0; i < fb_helper->crtc_count; i++) {
  		modeset = &fb_helper->crtc_info[i].mode_set;
  		if (modeset->num_connectors == 0) {
  			BUG_ON(modeset->fb);
  			BUG_ON(modeset->num_connectors);
  			if (modeset->mode)
  				drm_mode_destroy(dev, modeset->mode);
  			modeset->mode = NULL;
  		}
  	}
  out:
  	kfree(crtcs);
  	kfree(modes);
  	kfree(enabled);
  }
  
  /**
   * drm_fb_helper_initial_config - setup a sane initial connector configuration
   * @fb_helper: fb_helper device struct
   * @bpp_sel: bpp value to use for the framebuffer configuration
   *
   * Scans the CRTCs and connectors and tries 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.
   *
   * Note that this also registers the fbdev and so allows userspace to call into
   * the driver through the fbdev interfaces.
   *
   * This function will call down into the ->fb_probe callback to let
   * the driver allocate and initialize the fbdev info structure and the drm
   * framebuffer used to back the fbdev. drm_fb_helper_fill_var() and
   * drm_fb_helper_fill_fix() are provided as helpers to setup simple default
   * values for the fbdev info structure.
   *
   * 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;
  
  	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)
  		dev_info(fb_helper->dev->dev, "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);
  
  /**
   * drm_fb_helper_hotplug_event - respond to a hotplug notification by
   *                               probing all the outputs attached to the fb
   * @fb_helper: the drm_fb_helper
   *
   * Scan the connectors attached to the fb_helper and try to put together a
   * setup after *notification of a change in output configuration.
   *
   * Called at runtime, takes the mode config locks to be able to check/change the
   * modeset configuration. Must be run from process context (which usually means
   * either the output polling work or a work item launched from the driver's
   * hotplug interrupt).
   *
   * Note that the driver must ensure that this is only called _after_ the fb has
   * been fully set up, i.e. after the call to drm_fb_helper_initial_config.
   *
   * RETURNS:
   * 0 on success and a non-zero error code otherwise.
   */
  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;
  
  	if (!fb_helper->fb)
  		return 0;
  
  	mutex_lock(&fb_helper->dev->mode_config.mutex);
  	if (!drm_fb_helper_is_bound(fb_helper)) {
  		fb_helper->delayed_hotplug = true;
  		mutex_unlock(&fb_helper->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);
  	mutex_unlock(&fb_helper->dev->mode_config.mutex);
  
  	drm_modeset_lock_all(dev);
  	drm_setup_crtcs(fb_helper);
  	drm_modeset_unlock_all(dev);
  	drm_fb_helper_set_par(fb_helper->fbdev);
  
  	return 0;
  }
  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
  