fishHEADmaster

1 files changed, 1599 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_fb_helper.c b/drivers/gpu/drm/drm_fb_helper.c
new file mode 100644
index 0000000..2312f1e
--- /dev/null
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -0,0 +1,1599 @@
+/*
+ * 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(CPTCFG_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