DRM: i915: add mode setting support

This commit adds i915 driver support for the DRM mode setting APIs.
Currently, VGA, LVDS, SDVO DVI & VGA, TV and DVO LVDS outputs are
supported.  HDMI, DisplayPort and additional SDVO output support will
follow.

Support for the mode setting code is controlled by the new 'modeset'
module option.  A new config option, CONFIG_DRM_I915_KMS controls the
default behavior, and whether a PCI ID list is built into the module for
use by user level module utilities.

Note that if mode setting is enabled, user level drivers that access
display registers directly or that don't use the kernel graphics memory
manager will likely corrupt kernel graphics memory, disrupt output
configuration (possibly leading to hangs and/or blank displays), and
prevent panic/oops messages from appearing.  So use caution when
enabling this code; be sure your user level code supports the new
interfaces.

A new SysRq key, 'g', provides emergency support for switching back to
the kernel's framebuffer console; which is useful for testing.

Co-authors: Dave Airlie <airlied@linux.ie>, Hong Liu <hong.liu@intel.com>

Signed-off-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Signed-off-by: Eric Anholt <eric@anholt.net>
Signed-off-by: Dave Airlie <airlied@redhat.com>

1 files changed, 926 insertions, 0 deletions

diff --git a/drivers/gpu/drm/i915/intel_fb.c b/drivers/gpu/drm/i915/intel_fb.c
new file mode 100644
index 000000000000..a89ebea7b76d
--- /dev/null
+++ b/drivers/gpu/drm/i915/intel_fb.c
@@ -0,0 +1,926 @@
+/*
+ * Copyright © 2007 David Airlie
+ *
+ * Permission is hereby granted, free of charge, to any person obtaining a
+ * copy of this software and associated documentation files (the "Software"),
+ * to deal in the Software without restriction, including without limitation
+ * the rights to use, copy, modify, merge, publish, distribute, sublicense,
+ * and/or sell copies of the Software, and to permit persons to whom the
+ * Software is furnished to do so, subject to the following conditions:
+ *
+ * The above copyright notice and this permission notice (including the next
+ * paragraph) shall be included in all copies or substantial portions of the
+ * Software.
+ *
+ * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+ * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+ * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.  IN NO EVENT SHALL
+ * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+ * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING
+ * FROM, OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
+ * DEALINGS IN THE SOFTWARE.
+ *
+ * Authors:
+ *     David Airlie
+ */
+
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/errno.h>
+#include <linux/string.h>
+#include <linux/mm.h>
+#include <linux/tty.h>
+#include <linux/slab.h>
+#include <linux/sysrq.h>
+#include <linux/delay.h>
+#include <linux/fb.h>
+#include <linux/init.h>
+
+#include "drmP.h"
+#include "drm.h"
+#include "drm_crtc.h"
+#include "intel_drv.h"
+#include "i915_drm.h"
+#include "i915_drv.h"
+
+struct intelfb_par {
+        struct drm_device *dev;
+        struct drm_display_mode *our_mode;
+        struct intel_framebuffer *intel_fb;
+        int crtc_count;
+        /* crtc currently bound to this */
+        uint32_t crtc_ids[2];
+};
+
+static int intelfb_setcolreg(unsigned regno, unsigned red, unsigned green,
+                        unsigned blue, unsigned transp,
+                        struct fb_info *info)
+{
+        struct intelfb_par *par = info->par;
+        struct drm_device *dev = par->dev;
+        struct drm_crtc *crtc;
+        int i;
+
+        list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
+                struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
+                struct drm_mode_set *modeset = &intel_crtc->mode_set;
+                struct drm_framebuffer *fb = modeset->fb;
+
+                for (i = 0; i < par->crtc_count; i++)
+                        if (crtc->base.id == par->crtc_ids[i])
+                                break;
+
+                if (i == par->crtc_count)
+                        continue;
+
+
+                if (regno > 255)
+                        return 1;
+
+                if (fb->depth == 8) {
+                        intel_crtc_fb_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 & 0xff00) << 8) |
+                                        (green & 0xff00) |
+                                        ((blue  & 0xff00) >> 8);
+                                break;
+                        }
+                }
+        }
+        return 0;
+}
+
+static int intelfb_check_var(struct fb_var_screeninfo *var,
+                        struct fb_info *info)
+{
+        struct intelfb_par *par = info->par;
+        struct intel_framebuffer *intel_fb = par->intel_fb;
+        struct drm_framebuffer *fb = &intel_fb->base;
+        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;
+}
+
+/* this will let fbcon do the mode init */
+/* FIXME: take mode config lock? */
+static int intelfb_set_par(struct fb_info *info)
+{
+        struct intelfb_par *par = info->par;
+        struct drm_device *dev = par->dev;
+        struct fb_var_screeninfo *var = &info->var;
+        int i;
+
+        DRM_DEBUG("%d %d\n", var->xres, var->pixclock);
+
+        if (var->pixclock != -1) {
+
+                DRM_ERROR("PIXEL CLCOK SET\n");
+                return -EINVAL;
+        } else {
+                struct drm_crtc *crtc;
+                int ret;
+
+                list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
+                        struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
+
+                        for (i = 0; i < par->crtc_count; i++)
+                                if (crtc->base.id == par->crtc_ids[i])
+                                        break;
+
+                        if (i == par->crtc_count)
+                                continue;
+
+                        if (crtc->fb == intel_crtc->mode_set.fb) {
+                                mutex_lock(&dev->mode_config.mutex);
+                                ret = crtc->funcs->set_config(&intel_crtc->mode_set);
+                                mutex_unlock(&dev->mode_config.mutex);
+                                if (ret)
+                                        return ret;
+                        }
+                }
+                return 0;
+        }
+}
+
+static int intelfb_pan_display(struct fb_var_screeninfo *var,
+                                struct fb_info *info)
+{
+        struct intelfb_par *par = info->par;
+        struct drm_device *dev = par->dev;
+        struct drm_mode_set *modeset;
+        struct drm_crtc *crtc;
+        struct intel_crtc *intel_crtc;
+        int ret = 0;
+        int i;
+
+        list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
+                for (i = 0; i < par->crtc_count; i++)
+                        if (crtc->base.id == par->crtc_ids[i])
+                                break;
+
+                if (i == par->crtc_count)
+                        continue;
+
+                intel_crtc = to_intel_crtc(crtc);
+                modeset = &intel_crtc->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;
+}
+
+static void intelfb_on(struct fb_info *info)
+{
+        struct intelfb_par *par = info->par;
+        struct drm_device *dev = par->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 < par->crtc_count; i++)
+                        if (crtc->base.id == par->crtc_ids[i])
+                                break;
+
+                crtc_funcs->dpms(crtc, DRM_MODE_DPMS_ON);
+
+                /* Found a CRTC on this fb, now find encoders */
+                list_for_each_entry(encoder, &dev->mode_config.encoder_list, head) {
+                        if (encoder->crtc == crtc) {
+                                struct drm_encoder_helper_funcs *encoder_funcs;
+                                encoder_funcs = encoder->helper_private;
+                                encoder_funcs->dpms(encoder, DRM_MODE_DPMS_ON);
+                        }
+                }
+        }
+}
+
+static void intelfb_off(struct fb_info *info, int dpms_mode)
+{
+        struct intelfb_par *par = info->par;
+        struct drm_device *dev = par->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 < par->crtc_count; i++)
+                        if (crtc->base.id == par->crtc_ids[i])
+                                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;
+                                encoder_funcs->dpms(encoder, dpms_mode);
+                        }
+                }
+                if (dpms_mode == DRM_MODE_DPMS_OFF)
+                        crtc_funcs->dpms(crtc, dpms_mode);
+        }
+}
+
+int intelfb_blank(int blank, struct fb_info *info)
+{
+        switch (blank) {
+        case FB_BLANK_UNBLANK:
+                intelfb_on(info);
+                break;
+        case FB_BLANK_NORMAL:
+                intelfb_off(info, DRM_MODE_DPMS_STANDBY);
+                break;
+        case FB_BLANK_HSYNC_SUSPEND:
+                intelfb_off(info, DRM_MODE_DPMS_STANDBY);
+                break;
+        case FB_BLANK_VSYNC_SUSPEND:
+                intelfb_off(info, DRM_MODE_DPMS_SUSPEND);
+                break;
+        case FB_BLANK_POWERDOWN:
+                intelfb_off(info, DRM_MODE_DPMS_OFF);
+                break;
+        }
+        return 0;
+}
+
+static struct fb_ops intelfb_ops = {
+        .owner = THIS_MODULE,
+        .fb_check_var = intelfb_check_var,
+        .fb_set_par = intelfb_set_par,
+        .fb_setcolreg = intelfb_setcolreg,
+        .fb_fillrect = cfb_fillrect,
+        .fb_copyarea = cfb_copyarea,
+        .fb_imageblit = cfb_imageblit,
+        .fb_pan_display = intelfb_pan_display,
+        .fb_blank = intelfb_blank,
+};
+
+/**
+ * Curretly it is assumed that the old framebuffer is reused.
+ *
+ * LOCKING
+ * caller should hold the mode config lock.
+ *
+ */
+int intelfb_resize(struct drm_device *dev, struct drm_crtc *crtc)
+{
+        struct fb_info *info;
+        struct drm_framebuffer *fb;
+        struct drm_display_mode *mode = crtc->desired_mode;
+
+        fb = crtc->fb;
+        if (!fb)
+                return 1;
+
+        info = fb->fbdev;
+        if (!info)
+                return 1;
+
+        if (!mode)
+                return 1;
+
+        info->var.xres = mode->hdisplay;
+        info->var.right_margin = mode->hsync_start - mode->hdisplay;
+        info->var.hsync_len = mode->hsync_end - mode->hsync_start;
+        info->var.left_margin = mode->htotal - mode->hsync_end;
+        info->var.yres = mode->vdisplay;
+        info->var.lower_margin = mode->vsync_start - mode->vdisplay;
+        info->var.vsync_len = mode->vsync_end - mode->vsync_start;
+        info->var.upper_margin = mode->vtotal - mode->vsync_end;
+        info->var.pixclock = 10000000 / mode->htotal * 1000 / mode->vtotal * 100;
+        /* avoid overflow */
+        info->var.pixclock = info->var.pixclock * 1000 / mode->vrefresh;
+
+        return 0;
+}
+EXPORT_SYMBOL(intelfb_resize);
+
+static struct drm_mode_set kernelfb_mode;
+
+int intelfb_panic(struct notifier_block *n, unsigned long ununsed,
+                  void *panic_str)
+{
+        DRM_ERROR("panic occurred, switching back to text console\n");
+
+        intelfb_restore();
+        return 0;
+}
+EXPORT_SYMBOL(intelfb_panic);
+
+static struct notifier_block paniced = {
+        .notifier_call = intelfb_panic,
+};
+
+int intelfb_create(struct drm_device *dev, uint32_t fb_width,
+                   uint32_t fb_height, uint32_t surface_width,
+                   uint32_t surface_height,
+                   struct intel_framebuffer **intel_fb_p)
+{
+        struct fb_info *info;
+        struct intelfb_par *par;
+        struct drm_framebuffer *fb;
+        struct intel_framebuffer *intel_fb;
+        struct drm_mode_fb_cmd mode_cmd;
+        struct drm_gem_object *fbo = NULL;
+        struct drm_i915_gem_object *obj_priv;
+        struct device *device = &dev->pdev->dev;
+        int size, ret, mmio_bar = IS_I9XX(dev) ? 0 : 1;
+
+        mode_cmd.width = surface_width;
+        mode_cmd.height = surface_height;
+
+        mode_cmd.bpp = 32;
+        mode_cmd.pitch = mode_cmd.width * ((mode_cmd.bpp + 1) / 8);
+        mode_cmd.depth = 24;
+
+        size = mode_cmd.pitch * mode_cmd.height;
+        size = ALIGN(size, PAGE_SIZE);
+        fbo = drm_gem_object_alloc(dev, size);
+        if (!fbo) {
+                printk(KERN_ERR "failed to allocate framebuffer\n");
+                ret = -ENOMEM;
+                goto out;
+        }
+        obj_priv = fbo->driver_private;
+
+        mutex_lock(&dev->struct_mutex);
+
+        ret = i915_gem_object_pin(fbo, PAGE_SIZE);
+        if (ret) {
+                DRM_ERROR("failed to pin fb: %d\n", ret);
+                goto out_unref;
+        }
+
+        /* Flush everything out, we'll be doing GTT only from now on */
+        i915_gem_object_set_to_gtt_domain(fbo, 1);
+
+        ret = intel_framebuffer_create(dev, &mode_cmd, &fb, fbo);
+        if (ret) {
+                DRM_ERROR("failed to allocate fb.\n");
+                goto out_unref;
+        }
+
+        list_add(&fb->filp_head, &dev->mode_config.fb_kernel_list);
+
+        intel_fb = to_intel_framebuffer(fb);
+        *intel_fb_p = intel_fb;
+
+        info = framebuffer_alloc(sizeof(struct intelfb_par), device);
+        if (!info) {
+                ret = -ENOMEM;
+                goto out_unref;
+        }
+
+        par = info->par;
+
+        strcpy(info->fix.id, "inteldrmfb");
+        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->flags = FBINFO_DEFAULT;
+
+        info->fbops = &intelfb_ops;
+
+        info->fix.line_length = fb->pitch;
+        info->fix.smem_start = dev->mode_config.fb_base + obj_priv->gtt_offset;
+        info->fix.smem_len = size;
+
+        info->flags = FBINFO_DEFAULT;
+
+        info->screen_base = ioremap_wc(dev->agp->base + obj_priv->gtt_offset,
+                                       size);
+        if (!info->screen_base) {
+                ret = -ENOSPC;
+                goto out_unref;
+        }
+        info->screen_size = size;
+
+//      memset(info->screen_base, 0, size);
+
+        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;
+
+        info->var.xres = fb_width;
+        info->var.yres = fb_height;
+
+        /* FIXME: we really shouldn't expose mmio space at all */
+        info->fix.mmio_start = pci_resource_start(dev->pdev, mmio_bar);
+        info->fix.mmio_len = pci_resource_len(dev->pdev, mmio_bar);
+
+        info->pixmap.size = 64*1024;
+        info->pixmap.buf_align = 8;
+        info->pixmap.access_align = 32;
+        info->pixmap.flags = FB_PIXMAP_SYSTEM;
+        info->pixmap.scan_align = 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;
+        }
+
+        fb->fbdev = info;
+
+        par->intel_fb = intel_fb;
+        par->dev = dev;
+
+        /* To allow resizeing without swapping buffers */
+        printk("allocated %dx%d fb: 0x%08x, bo %p\n", intel_fb->base.width,
+               intel_fb->base.height, obj_priv->gtt_offset, fbo);
+
+        mutex_unlock(&dev->struct_mutex);
+        return 0;
+
+out_unref:
+        drm_gem_object_unreference(fbo);
+        mutex_unlock(&dev->struct_mutex);
+out:
+        return ret;
+}
+
+static int intelfb_multi_fb_probe_crtc(struct drm_device *dev, struct drm_crtc *crtc)
+{
+        struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
+        struct intel_framebuffer *intel_fb;
+        struct drm_framebuffer *fb;
+        struct drm_connector *connector;
+        struct fb_info *info;
+        struct intelfb_par *par;
+        struct drm_mode_set *modeset;
+        unsigned int width, height;
+        int new_fb = 0;
+        int ret, i, conn_count;
+
+        if (!drm_helper_crtc_in_use(crtc))
+                return 0;
+
+        if (!crtc->desired_mode)
+                return 0;
+
+        width = crtc->desired_mode->hdisplay;
+        height = crtc->desired_mode->vdisplay;
+
+        /* is there an fb bound to this crtc already */
+        if (!intel_crtc->mode_set.fb) {
+                ret = intelfb_create(dev, width, height, width, height, &intel_fb);
+                if (ret)
+                        return -EINVAL;
+                new_fb = 1;
+        } else {
+                fb = intel_crtc->mode_set.fb;
+                intel_fb = to_intel_framebuffer(fb);
+                if ((intel_fb->base.width < width) || (intel_fb->base.height < height))
+                        return -EINVAL;
+        }
+
+        info = intel_fb->base.fbdev;
+        par = info->par;
+
+        modeset = &intel_crtc->mode_set;
+        modeset->fb = &intel_fb->base;
+        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 > INTELFB_CONN_LIMIT)
+                                        BUG();
+                        }
+        }
+
+        for (i = conn_count; i < INTELFB_CONN_LIMIT; i++)
+                modeset->connectors[i] = NULL;
+
+        par->crtc_ids[0] = crtc->base.id;
+
+        modeset->num_connectors = conn_count;
+        if (modeset->mode != modeset->crtc->desired_mode)
+                modeset->mode = modeset->crtc->desired_mode;
+
+        par->crtc_count = 1;
+
+        if (new_fb) {
+                info->var.pixclock = -1;
+                if (register_framebuffer(info) < 0)
+                        return -EINVAL;
+        } else
+                intelfb_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 */
+        kernelfb_mode = *modeset;
+        atomic_notifier_chain_register(&panic_notifier_list, &paniced);
+        printk(KERN_INFO "registered panic notifier\n");
+
+        return 0;
+}
+
+static int intelfb_multi_fb_probe(struct drm_device *dev)
+{
+
+        struct drm_crtc *crtc;
+        int ret = 0;
+
+        list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
+                ret = intelfb_multi_fb_probe_crtc(dev, crtc);
+                if (ret)
+                        return ret;
+        }
+        return ret;
+}
+
+static int intelfb_single_fb_probe(struct drm_device *dev)
+{
+        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 intel_framebuffer *intel_fb;
+        struct fb_info *info;
+        struct intelfb_par *par;
+        struct drm_mode_set *modeset = NULL;
+
+        DRM_DEBUG("\n");
+
+        /* 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))
+                        continue;
+
+                crtc_count++;
+                if (!crtc->desired_mode)
+                        continue;
+
+                /* Smallest mode determines console size... */
+                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;
+
+                /* ... but largest for memory allocation dimensions */
+                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;
+        }
+
+        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. */
+                DRM_DEBUG("no CRTCs available?\n");
+                return 0;
+        }
+
+//fail
+        /* Find the fb for our new config */
+        if (list_empty(&dev->mode_config.fb_kernel_list)) {
+                DRM_DEBUG("creating new fb (console size %dx%d, "
+                          "buffer size %dx%d)\n", fb_width, fb_height,
+                          surface_width, surface_height);
+                ret = intelfb_create(dev, fb_width, fb_height, surface_width,
+                                     surface_height, &intel_fb);
+                if (ret)
+                        return -EINVAL;
+                new_fb = 1;
+        } else {
+                struct drm_framebuffer *fb;
+
+                fb = list_first_entry(&dev->mode_config.fb_kernel_list,
+                                      struct drm_framebuffer, filp_head);
+                intel_fb = to_intel_framebuffer(fb);
+
+                /* 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("fb not large enough for console\n");
+                        return -EINVAL;
+                }
+        }
+// fail
+
+        info = intel_fb->base.fbdev;
+        par = info->par;
+
+        crtc_count = 0;
+        /*
+         * For each CRTC, set up the connector list for the CRTC's mode
+         * set configuration.
+         */
+        list_for_each_entry(crtc, &dev->mode_config.crtc_list, head) {
+                struct intel_crtc *intel_crtc = to_intel_crtc(crtc);
+
+                modeset = &intel_crtc->mode_set;
+                modeset->fb = &intel_fb->base;
+                conn_count = 0;
+                list_for_each_entry(connector, &dev->mode_config.connector_list,
+                                    head) {
+                        if (!connector->encoder)
+                                continue;
+
+                        if(connector->encoder->crtc == modeset->crtc) {
+                                modeset->connectors[conn_count++] = connector;
+                                if (conn_count > INTELFB_CONN_LIMIT)
+                                        BUG();
+                        }
+                }
+
+                /* Zero out remaining connector pointers */
+                for (i = conn_count; i < INTELFB_CONN_LIMIT; i++)
+                        modeset->connectors[i] = NULL;
+
+                par->crtc_ids[crtc_count++] = crtc->base.id;
+
+                modeset->num_connectors = conn_count;
+                if (modeset->mode != modeset->crtc->desired_mode)
+                        modeset->mode = modeset->crtc->desired_mode;
+        }
+        par->crtc_count = crtc_count;
+
+        if (new_fb) {
+                info->var.pixclock = -1;
+                if (register_framebuffer(info) < 0)
+                        return -EINVAL;
+        } else
+                intelfb_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 */
+        kernelfb_mode = *modeset;
+        atomic_notifier_chain_register(&panic_notifier_list, &paniced);
+        printk(KERN_INFO "registered panic notifier\n");
+
+        return 0;
+}
+
+/**
+ * intelfb_restore - restore the framebuffer console (kernel) config
+ *
+ * Restore's the kernel's fbcon mode, used for lastclose & panic paths.
+ */
+void intelfb_restore(void)
+{
+        drm_crtc_helper_set_config(&kernelfb_mode);
+}
+
+static void intelfb_sysrq(int dummy1, struct tty_struct *dummy3)
+{
+        intelfb_restore();
+}
+
+static struct sysrq_key_op sysrq_intelfb_restore_op = {
+        .handler = intelfb_sysrq,
+        .help_msg = "force fb",
+        .action_msg = "force restore of fb console",
+};
+
+int intelfb_probe(struct drm_device *dev)
+{
+        int ret;
+
+        DRM_DEBUG("\n");
+
+        /* something has changed in the lower levels of hell - deal with it
+           here */
+
+        /* two modes : a) 1 fb to rule all crtcs.
+                       b) one fb per crtc.
+           two actions 1) new connected device
+                       2) device removed.
+           case a/1 : if the fb surface isn't big enough - resize the surface fb.
+                      if the fb size isn't big enough - resize fb into surface.
+                      if everything big enough configure the new crtc/etc.
+           case a/2 : undo the configuration
+                      possibly resize down the fb to fit the new configuration.
+           case b/1 : see if it is on a new crtc - setup a new fb and add it.
+           case b/2 : teardown the new fb.
+        */
+
+        /* mode a first */
+        /* search for an fb */
+        if (i915_fbpercrtc == 1) {
+                ret = intelfb_multi_fb_probe(dev);
+        } else {
+                ret = intelfb_single_fb_probe(dev);
+        }
+
+        register_sysrq_key('g', &sysrq_intelfb_restore_op);
+
+        return ret;
+}
+EXPORT_SYMBOL(intelfb_probe);
+
+int intelfb_remove(struct drm_device *dev, struct drm_framebuffer *fb)
+{
+        struct fb_info *info;
+
+        if (!fb)
+                return -EINVAL;
+
+        info = fb->fbdev;
+
+        if (info) {
+                unregister_framebuffer(info);
+                iounmap(info->screen_base);
+                framebuffer_release(info);
+        }
+
+        atomic_notifier_chain_unregister(&panic_notifier_list, &paniced);
+        memset(&kernelfb_mode, 0, sizeof(struct drm_mode_set));
+        return 0;
+}
+EXPORT_SYMBOL(intelfb_remove);
+MODULE_LICENSE("GPL and additional rights");