drm/kms: move driver specific fb common code to helper functions (v2)

Initially I always meant this code to be shared, but things
ran away from me before I got to it.

This refactors the i915 and radeon kms fbdev interaction layers
out into generic helpers + driver specific pieces.

It moves all the panic/sysrq enhancements to the core file,
and stores a linked list of kernel fbs. This could possibly be
improved to only store the fb which has fbcon on it for panics
etc.

radeon retains some specific codes used for a big endian
workaround.

changes:
fix oops in v1
fix freeing path for crtc_info

Reviewed-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 697 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 00000000000..d6ffea74a50
--- /dev/null
+++ b/drivers/gpu/drm/drm_fb_helper.c
@@ -0,0 +1,697 @@
+/*
+ * Copyright (c) 2006-2009 Red Hat Inc.
+ * Copyright (c) 2006-2008 Intel Corporation
+ * Copyright (c) 2007 Dave Airlie <airlied@linux.ie>
+ *
+ * DRM framebuffer helper functions
+ *
+ * Permission to use, copy, modify, distribute, and sell this software and its
+ * documentation for any purpose is hereby granted without fee, provided that
+ * the above copyright notice appear in all copies and that both that copyright
+ * notice and this permission notice appear in supporting documentation, and
+ * that the name of the copyright holders not be used in advertising or
+ * publicity pertaining to distribution of the software without specific,
+ * written prior permission.  The copyright holders make no representations
+ * about the suitability of this software for any purpose.  It is provided "as
+ * is" without express or implied warranty.
+ *
+ * THE COPYRIGHT HOLDERS DISCLAIM ALL WARRANTIES WITH REGARD TO THIS SOFTWARE,
+ * INCLUDING ALL IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS, IN NO
+ * EVENT SHALL THE COPYRIGHT HOLDERS BE LIABLE FOR ANY SPECIAL, INDIRECT OR
+ * CONSEQUENTIAL DAMAGES OR ANY DAMAGES WHATSOEVER RESULTING FROM LOSS OF USE,
+ * DATA OR PROFITS, WHETHER IN AN ACTION OF CONTRACT, NEGLIGENCE OR OTHER
+ * TORTIOUS ACTION, ARISING OUT OF OR IN CONNECTION WITH THE USE OR PERFORMANCE
+ * OF THIS SOFTWARE.
+ *
+ * Authors:
+ *      Dave Airlie <airlied@linux.ie>
+ *      Jesse Barnes <jesse.barnes@intel.com>
+ */
+#include <linux/sysrq.h>
+#include <linux/fb.h>
+#include "drmP.h"
+#include "drm_crtc.h"
+#include "drm_fb_helper.h"
+#include "drm_crtc_helper.h"
+
+static LIST_HEAD(kernel_fb_helper_list);
+
+bool drm_fb_helper_force_kernel_mode(void)
+{
+	int i = 0;
+	bool ret, error = false;
+	struct drm_fb_helper *helper;
+
+	if (list_empty(&kernel_fb_helper_list))
+		return false;
+
+	list_for_each_entry(helper, &kernel_fb_helper_list, kernel_fb_list) {
+		for (i = 0; i < helper->crtc_count; i++) {
+			struct drm_mode_set *mode_set = &helper->crtc_info[i].mode_set;
+			ret = drm_crtc_helper_set_config(mode_set);
+			if (ret)
+				error = true;
+		}
+	}
+	return error;
+}
+
+int drm_fb_helper_panic(struct notifier_block *n, unsigned long ununsed,
+			void *panic_str)
+{
+	DRM_ERROR("panic occurred, switching back to text console\n");
+	return drm_fb_helper_force_kernel_mode();
+	return 0;
+}
+EXPORT_SYMBOL(drm_fb_helper_panic);
+
+static struct notifier_block paniced = {
+	.notifier_call = drm_fb_helper_panic,
+};
+
+/**
+ * drm_fb_helper_restore - restore the framebuffer console (kernel) config
+ *
+ * Restore's the kernel's fbcon mode, used for lastclose & panic paths.
+ */
+void drm_fb_helper_restore(void)
+{
+	bool ret;
+	ret = drm_fb_helper_force_kernel_mode();
+	if (ret == true)
+		DRM_ERROR("Failed to restore crtc configuration\n");
+}
+EXPORT_SYMBOL(drm_fb_helper_restore);
+
+static void drm_fb_helper_restore_work_fn(struct work_struct *ignored)
+{
+	drm_fb_helper_restore();
+}
+static DECLARE_WORK(drm_fb_helper_restore_work, drm_fb_helper_restore_work_fn);
+
+static void drm_fb_helper_sysrq(int dummy1, struct tty_struct *dummy3)
+{
+	schedule_work(&drm_fb_helper_restore_work);
+}
+
+static struct sysrq_key_op sysrq_drm_fb_helper_restore_op = {
+	.handler = drm_fb_helper_sysrq,
+	.help_msg = "force-fb(V)",
+	.action_msg = "Restore framebuffer console",
+};
+
+static void drm_fb_helper_on(struct fb_info *info)
+{
+	struct drm_fb_helper *fb_helper = info->par;
+	struct drm_device *dev = fb_helper->dev;
+	struct drm_crtc *crtc;
+	struct drm_encoder *encoder;
+	int i;
+
+	/*
+	 * For each CRTC in this fb, turn the crtc on then,
+	 * find all associated encoders and turn them on.
+	 */
+	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
+		struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
+
+		for (i = 0; i < fb_helper->crtc_count; i++) {
+			if (crtc->base.id == fb_helper->crtc_info[i].crtc_id)
+				break;
+		}
+
+		mutex_lock(&dev->mode_config.mutex);
+		crtc_funcs->dpms(crtc, DRM_MODE_DPMS_ON);
+		mutex_unlock(&dev->mode_config.mutex);
+
+		/* Found a CRTC on this fb, now find encoders */
+		list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
+			if (encoder->crtc == crtc) {
+				struct drm_encoder_helper_funcs *encoder_funcs;
+
+				encoder_funcs = encoder->helper_private;
+				mutex_lock(&dev->mode_config.mutex);
+				encoder_funcs->dpms(encoder, DRM_MODE_DPMS_ON);
+				mutex_unlock(&dev->mode_config.mutex);
+			}
+		}
+	}
+}
+
+static void drm_fb_helper_off(struct fb_info *info, int dpms_mode)
+{
+	struct drm_fb_helper *fb_helper = info->par;
+	struct drm_device *dev = fb_helper->dev;
+	struct drm_crtc *crtc;
+	struct drm_encoder *encoder;
+	int i;
+
+	/*
+	 * For each CRTC in this fb, find all associated encoders
+	 * and turn them off, then turn off the CRTC.
+	 */
+	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
+		struct drm_crtc_helper_funcs *crtc_funcs = crtc->helper_private;
+
+		for (i = 0; i < fb_helper->crtc_count; i++) {
+			if (crtc->base.id == fb_helper->crtc_info[i].crtc_id)
+				break;
+		}
+
+		/* Found a CRTC on this fb, now find encoders */
+		list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
+			if (encoder->crtc == crtc) {
+				struct drm_encoder_helper_funcs *encoder_funcs;
+
+				encoder_funcs = encoder->helper_private;
+				mutex_lock(&dev->mode_config.mutex);
+				encoder_funcs->dpms(encoder, dpms_mode);
+				mutex_unlock(&dev->mode_config.mutex);
+			}
+		}
+		if (dpms_mode == DRM_MODE_DPMS_OFF) {
+			mutex_lock(&dev->mode_config.mutex);
+			crtc_funcs->dpms(crtc, dpms_mode);
+			mutex_unlock(&dev->mode_config.mutex);
+		}
+	}
+}
+
+int drm_fb_helper_blank(int blank, struct fb_info *info)
+{
+	switch (blank) {
+	case FB_BLANK_UNBLANK:
+		drm_fb_helper_on(info);
+		break;
+	case FB_BLANK_NORMAL:
+		drm_fb_helper_off(info, DRM_MODE_DPMS_STANDBY);
+		break;
+	case FB_BLANK_HSYNC_SUSPEND:
+		drm_fb_helper_off(info, DRM_MODE_DPMS_STANDBY);
+		break;
+	case FB_BLANK_VSYNC_SUSPEND:
+		drm_fb_helper_off(info, DRM_MODE_DPMS_SUSPEND);
+		break;
+	case FB_BLANK_POWERDOWN:
+		drm_fb_helper_off(info, DRM_MODE_DPMS_OFF);
+		break;
+	}
+	return 0;
+}
+EXPORT_SYMBOL(drm_fb_helper_blank);
+
+static void drm_fb_helper_crtc_free(struct drm_fb_helper *helper)
+{
+	int i;
+
+	for (i = 0; i < helper->crtc_count; i++)
+		kfree(helper->crtc_info[i].mode_set.connectors);
+	kfree(helper->crtc_info);
+}
+
+int drm_fb_helper_init_crtc_count(struct drm_fb_helper *helper, int crtc_count, int max_conn_count)
+{
+	struct drm_device *dev = helper->dev;
+	struct drm_crtc *crtc;
+	int ret = 0;
+	int i;
+
+	helper->crtc_info = kcalloc(crtc_count, sizeof(struct drm_fb_helper_crtc), GFP_KERNEL);
+	if (!helper->crtc_info)
+		return -ENOMEM;
+
+	helper->crtc_count = crtc_count;
+
+	for (i = 0; i < crtc_count; i++) {
+		helper->crtc_info[i].mode_set.connectors =
+			kcalloc(max_conn_count,
+				sizeof(struct drm_connector *),
+				GFP_KERNEL);
+
+		if (!helper->crtc_info[i].mode_set.connectors) {
+			ret = -ENOMEM;
+			goto out_free;
+		}
+		helper->crtc_info[i].mode_set.num_connectors = 0;
+	}
+
+	i = 0;
+	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
+		helper->crtc_info[i].crtc_id = crtc->base.id;
+		helper->crtc_info[i].mode_set.crtc = crtc;
+		i++;
+	}
+	helper->conn_limit = max_conn_count;
+	return 0;
+out_free:
+	drm_fb_helper_crtc_free(helper);
+	return -ENOMEM;
+}
+EXPORT_SYMBOL(drm_fb_helper_init_crtc_count);
+
+int drm_fb_helper_setcolreg(unsigned regno,
+			    unsigned red,
+			    unsigned green,
+			    unsigned blue,
+			    unsigned transp,
+			    struct fb_info *info)
+{
+	struct drm_fb_helper *fb_helper = info->par;
+	struct drm_device *dev = fb_helper->dev;
+	struct drm_crtc *crtc;
+	int i;
+
+	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
+		struct drm_framebuffer *fb = fb_helper->fb;
+
+		for (i = 0; i < fb_helper->crtc_count; i++) {
+			if (crtc->base.id == fb_helper->crtc_info[i].crtc_id)
+				break;
+		}
+		if (i == fb_helper->crtc_count)
+			continue;
+
+		if (regno > 255)
+			return 1;
+
+		if (fb->depth == 8) {
+			fb_helper->funcs->gamma_set(crtc, red, green, blue, regno);
+			return 0;
+		}
+
+		if (regno < 16) {
+			switch (fb->depth) {
+			case 15:
+				fb->pseudo_palette[regno] = ((red & 0xf800) >> 1) |
+					((green & 0xf800) >>  6) |
+					((blue & 0xf800) >> 11);
+				break;
+			case 16:
+				fb->pseudo_palette[regno] = (red & 0xf800) |
+					((green & 0xfc00) >>  5) |
+					((blue  & 0xf800) >> 11);
+				break;
+			case 24:
+			case 32:
+				fb->pseudo_palette[regno] =
+					(((red >> 8) & 0xff) << info->var.red.offset) |
+					(((green >> 8) & 0xff) << info->var.green.offset) |
+					(((blue >> 8) & 0xff) << info->var.blue.offset);
+				break;
+			}
+		}
+	}
+	return 0;
+}
+EXPORT_SYMBOL(drm_fb_helper_setcolreg);
+
+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 == -1 || !var->pixclock)
+		return -EINVAL;
+
+	/* Need to resize the fb object !!! */
+	if (var->xres > fb->width || var->yres > fb->height) {
+		DRM_ERROR("Requested width/height is greater than current fb "
+			   "object %dx%d > %dx%d\n", var->xres, var->yres,
+			   fb->width, fb->height);
+		DRM_ERROR("Need resizing code.\n");
+		return -EINVAL;
+	}
+
+	switch (var->bits_per_pixel) {
+	case 16:
+		depth = (var->green.length == 6) ? 16 : 15;
+		break;
+	case 32:
+		depth = (var->transp.length > 0) ? 32 : 24;
+		break;
+	default:
+		depth = var->bits_per_pixel;
+		break;
+	}
+
+	switch (depth) {
+	case 8:
+		var->red.offset = 0;
+		var->green.offset = 0;
+		var->blue.offset = 0;
+		var->red.length = 8;
+		var->green.length = 8;
+		var->blue.length = 8;
+		var->transp.length = 0;
+		var->transp.offset = 0;
+		break;
+	case 15:
+		var->red.offset = 10;
+		var->green.offset = 5;
+		var->blue.offset = 0;
+		var->red.length = 5;
+		var->green.length = 5;
+		var->blue.length = 5;
+		var->transp.length = 1;
+		var->transp.offset = 15;
+		break;
+	case 16:
+		var->red.offset = 11;
+		var->green.offset = 5;
+		var->blue.offset = 0;
+		var->red.length = 5;
+		var->green.length = 6;
+		var->blue.length = 5;
+		var->transp.length = 0;
+		var->transp.offset = 0;
+		break;
+	case 24:
+		var->red.offset = 16;
+		var->green.offset = 8;
+		var->blue.offset = 0;
+		var->red.length = 8;
+		var->green.length = 8;
+		var->blue.length = 8;
+		var->transp.length = 0;
+		var->transp.offset = 0;
+		break;
+	case 32:
+		var->red.offset = 16;
+		var->green.offset = 8;
+		var->blue.offset = 0;
+		var->red.length = 8;
+		var->green.length = 8;
+		var->blue.length = 8;
+		var->transp.length = 8;
+		var->transp.offset = 24;
+		break;
+	default:
+		return -EINVAL;
+	}
+	return 0;
+}
+EXPORT_SYMBOL(drm_fb_helper_check_var);
+
+/* this will let fbcon do the mode init */
+int drm_fb_helper_set_par(struct fb_info *info)
+{
+	struct drm_fb_helper *fb_helper = info->par;
+	struct drm_device *dev = fb_helper->dev;
+	struct fb_var_screeninfo *var = &info->var;
+	struct drm_crtc *crtc;
+	int ret;
+	int i;
+
+	if (var->pixclock != -1) {
+		DRM_ERROR("PIXEL CLCOK SET\n");
+		return -EINVAL;
+	}
+
+	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
+
+		for (i = 0; i < fb_helper->crtc_count; i++) {
+			if (crtc->base.id == fb_helper->crtc_info[i].crtc_id)
+				break;
+		}
+		if (i == fb_helper->crtc_count)
+			continue;
+
+		if (crtc->fb == fb_helper->crtc_info[i].mode_set.fb) {
+			mutex_lock(&dev->mode_config.mutex);
+			ret = crtc->funcs->set_config(&fb_helper->crtc_info->mode_set);
+			mutex_unlock(&dev->mode_config.mutex);
+			if (ret)
+				return ret;
+		}
+	}
+	return 0;
+}
+EXPORT_SYMBOL(drm_fb_helper_set_par);
+
+int drm_fb_helper_pan_display(struct fb_var_screeninfo *var,
+			      struct fb_info *info)
+{
+	struct drm_fb_helper *fb_helper = info->par;
+	struct drm_device *dev = fb_helper->dev;
+	struct drm_mode_set *modeset;
+	struct drm_crtc *crtc;
+	int ret = 0;
+	int i;
+
+	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
+		for (i = 0; i < fb_helper->crtc_count; i++) {
+			if (crtc->base.id == fb_helper->crtc_info[i].crtc_id)
+				break;
+		}
+
+		if (i == fb_helper->crtc_count)
+			continue;
+
+		modeset = &fb_helper->crtc_info[i].mode_set;
+
+		modeset->x = var->xoffset;
+		modeset->y = var->yoffset;
+
+		if (modeset->num_connectors) {
+			mutex_lock(&dev->mode_config.mutex);
+			ret = crtc->funcs->set_config(modeset);
+			mutex_unlock(&dev->mode_config.mutex);
+			if (!ret) {
+				info->var.xoffset = var->xoffset;
+				info->var.yoffset = var->yoffset;
+			}
+		}
+	}
+	return ret;
+}
+EXPORT_SYMBOL(drm_fb_helper_pan_display);
+
+int drm_fb_helper_single_fb_probe(struct drm_device *dev,
+				  int (*fb_create)(struct drm_device *dev,
+						   uint32_t fb_width,
+						   uint32_t fb_height,
+						   uint32_t surface_width,
+						   uint32_t surface_height,
+						   struct drm_framebuffer **fb_ptr))
+{
+	struct drm_crtc *crtc;
+	struct drm_connector *connector;
+	unsigned int fb_width = (unsigned)-1, fb_height = (unsigned)-1;
+	unsigned int surface_width = 0, surface_height = 0;
+	int new_fb = 0;
+	int crtc_count = 0;
+	int ret, i, conn_count = 0;
+	struct fb_info *info;
+	struct drm_framebuffer *fb;
+	struct drm_mode_set *modeset = NULL;
+	struct drm_fb_helper *fb_helper;
+
+	/* first up get a count of crtcs now in use and new min/maxes width/heights */
+	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
+		if (drm_helper_crtc_in_use(crtc)) {
+			if (crtc->desired_mode) {
+				if (crtc->desired_mode->hdisplay < fb_width)
+					fb_width = crtc->desired_mode->hdisplay;
+
+				if (crtc->desired_mode->vdisplay < fb_height)
+					fb_height = crtc->desired_mode->vdisplay;
+
+				if (crtc->desired_mode->hdisplay > surface_width)
+					surface_width = crtc->desired_mode->hdisplay;
+
+				if (crtc->desired_mode->vdisplay > surface_height)
+					surface_height = crtc->desired_mode->vdisplay;
+			}
+			crtc_count++;
+		}
+	}
+
+	if (crtc_count == 0 || fb_width == -1 || fb_height == -1) {
+		/* hmm everyone went away - assume VGA cable just fell out
+		   and will come back later. */
+		return 0;
+	}
+
+	/* do we have an fb already? */
+	if (list_empty(&dev->mode_config.fb_kernel_list)) {
+		ret = (*fb_create)(dev, fb_width, fb_height, surface_width,
+				   surface_height, &fb);
+		if (ret)
+			return -EINVAL;
+		new_fb = 1;
+	} else {
+		fb = list_first_entry(&dev->mode_config.fb_kernel_list,
+				      struct drm_framebuffer, filp_head);
+
+		/* if someone hotplugs something bigger than we have already allocated, we are pwned.
+		   As really we can't resize an fbdev that is in the wild currently due to fbdev
+		   not really being designed for the lower layers moving stuff around under it.
+		   - so in the grand style of things - punt. */
+		if ((fb->width < surface_width) ||
+		    (fb->height < surface_height)) {
+			DRM_ERROR("Framebuffer not large enough to scale console onto.\n");
+			return -EINVAL;
+		}
+	}
+
+	info = fb->fbdev;
+	fb_helper = info->par;
+
+	crtc_count = 0;
+	/* okay we need to setup new connector sets in the crtcs */
+	list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
+		modeset = &fb_helper->crtc_info[crtc_count].mode_set;
+		modeset->fb = fb;
+		conn_count = 0;
+		list_for_each_entry(connector, &dev->mode_config.connector_list, head) {
+			if (connector->encoder)
+				if (connector->encoder->crtc == modeset->crtc) {
+					modeset->connectors[conn_count] = connector;
+					conn_count++;
+					if (conn_count > fb_helper->conn_limit)
+						BUG();
+				}
+		}
+
+		for (i = conn_count; i < fb_helper->conn_limit; i++)
+			modeset->connectors[i] = NULL;
+
+		modeset->crtc = crtc;
+		crtc_count++;
+
+		modeset->num_connectors = conn_count;
+		if (modeset->crtc->desired_mode) {
+			if (modeset->mode)
+				drm_mode_destroy(dev, modeset->mode);
+			modeset->mode = drm_mode_duplicate(dev,
+							   modeset->crtc->desired_mode);
+		}
+	}
+	fb_helper->crtc_count = crtc_count;
+	fb_helper->fb = fb;
+
+	if (new_fb) {
+		info->var.pixclock = -1;
+		if (register_framebuffer(info) < 0)
+			return -EINVAL;
+	} else {
+		drm_fb_helper_set_par(info);
+	}
+	printk(KERN_INFO "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)) {
+		printk(KERN_INFO "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;
+}
+EXPORT_SYMBOL(drm_fb_helper_single_fb_probe);
+
+void drm_fb_helper_free(struct drm_fb_helper *helper)
+{
+	list_del(&helper->kernel_fb_list);
+	if (list_empty(&kernel_fb_helper_list)) {
+		printk(KERN_INFO "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(helper);
+}
+EXPORT_SYMBOL(drm_fb_helper_free);
+
+void drm_fb_helper_fill_fix(struct fb_info *info, uint32_t pitch)
+{
+	info->fix.type = FB_TYPE_PACKED_PIXELS;
+	info->fix.visual = FB_VISUAL_TRUECOLOR;
+	info->fix.type_aux = 0;
+	info->fix.xpanstep = 1; /* doing it in hw */
+	info->fix.ypanstep = 1; /* doing it in hw */
+	info->fix.ywrapstep = 0;
+	info->fix.accel = FB_ACCEL_I830;
+	info->fix.type_aux = 0;
+
+	info->fix.line_length = pitch;
+	return;
+}
+EXPORT_SYMBOL(drm_fb_helper_fill_fix);
+
+void drm_fb_helper_fill_var(struct fb_info *info, struct drm_framebuffer *fb,
+			    uint32_t fb_width, uint32_t fb_height)
+{
+	info->pseudo_palette = fb->pseudo_palette;
+	info->var.xres_virtual = fb->width;
+	info->var.yres_virtual = fb->height;
+	info->var.bits_per_pixel = fb->bits_per_pixel;
+	info->var.xoffset = 0;
+	info->var.yoffset = 0;
+	info->var.activate = FB_ACTIVATE_NOW;
+	info->var.height = -1;
+	info->var.width = -1;
+
+	switch (fb->depth) {
+	case 8:
+		info->var.red.offset = 0;
+		info->var.green.offset = 0;
+		info->var.blue.offset = 0;
+		info->var.red.length = 8; /* 8bit DAC */
+		info->var.green.length = 8;
+		info->var.blue.length = 8;
+		info->var.transp.offset = 0;
+		info->var.transp.length = 0;
+		break;
+	case 15:
+		info->var.red.offset = 10;
+		info->var.green.offset = 5;
+		info->var.blue.offset = 0;
+		info->var.red.length = 5;
+		info->var.green.length = 5;
+		info->var.blue.length = 5;
+		info->var.transp.offset = 15;
+		info->var.transp.length = 1;
+		break;
+	case 16:
+		info->var.red.offset = 11;
+		info->var.green.offset = 5;
+		info->var.blue.offset = 0;
+		info->var.red.length = 5;
+		info->var.green.length = 6;
+		info->var.blue.length = 5;
+		info->var.transp.offset = 0;
+		break;
+	case 24:
+		info->var.red.offset = 16;
+		info->var.green.offset = 8;
+		info->var.blue.offset = 0;
+		info->var.red.length = 8;
+		info->var.green.length = 8;
+		info->var.blue.length = 8;
+		info->var.transp.offset = 0;
+		info->var.transp.length = 0;
+		break;
+	case 32:
+		info->var.red.offset = 16;
+		info->var.green.offset = 8;
+		info->var.blue.offset = 0;
+		info->var.red.length = 8;
+		info->var.green.length = 8;
+		info->var.blue.length = 8;
+		info->var.transp.offset = 24;
+		info->var.transp.length = 8;
+		break;
+	default:
+		break;
+	}
+
+	info->var.xres = fb_width;
+	info->var.yres = fb_height;
+}
+EXPORT_SYMBOL(drm_fb_helper_fill_var);