DRM: add mode setting support

Add mode setting support to the DRM layer.

This is a fairly big chunk of work that allows DRM drivers to provide
full output control and configuration capabilities to userspace.  It was
motivated by several factors:
  - the fb layer's APIs aren't suited for anything but simple
    configurations
  - coordination between the fb layer, DRM layer, and various userspace
    drivers is poor to non-existent (radeonfb excepted)
  - user level mode setting drivers makes displaying panic & oops
    messages more difficult
  - suspend/resume of graphics state is possible in many more
    configurations with kernel level support

This commit just adds the core DRM part of the mode setting APIs.
Driver specific commits using these new structure and APIs will follow.

Co-authors: Jesse Barnes <jbarnes@virtuousgeek.org>, Jakob Bornecrantz <jakob@tungstengraphics.com>
Contributors: Alan Hourihane <alanh@tungstengraphics.com>, Maarten Maathuis <madman2003@gmail.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, 732 insertions, 0 deletions

diff --git a/drivers/gpu/drm/drm_edid.c b/drivers/gpu/drm/drm_edid.c
new file mode 100644
index 000000000000..681753e57dc7
--- /dev/null
+++ b/drivers/gpu/drm/drm_edid.c
@@ -0,0 +1,732 @@
+/*
+ * Copyright (c) 2006 Luc Verhaegen (quirks list)
+ * Copyright (c) 2007-2008 Intel Corporation
+ *   Jesse Barnes <jesse.barnes@intel.com>
+ *
+ * DDC probing routines (drm_ddc_read & drm_do_probe_ddc_edid) originally from
+ * FB layer.
+ *   Copyright (C) 2006 Dennis Munsie <dmunsie@cecropia.com>
+ *
+ * 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, sub license,
+ * 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 NON-INFRINGEMENT. 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.
+ */
+#include <linux/kernel.h>
+#include <linux/i2c.h>
+#include <linux/i2c-algo-bit.h>
+#include "drmP.h"
+#include "drm_edid.h"
+
+/*
+ * TODO:
+ *   - support EDID 1.4 (incl. CE blocks)
+ */
+
+/*
+ * EDID blocks out in the wild have a variety of bugs, try to collect
+ * them here (note that userspace may work around broken monitors first,
+ * but fixes should make their way here so that the kernel "just works"
+ * on as many displays as possible).
+ */
+
+/* First detailed mode wrong, use largest 60Hz mode */
+#define EDID_QUIRK_PREFER_LARGE_60              (1 << 0)
+/* Reported 135MHz pixel clock is too high, needs adjustment */
+#define EDID_QUIRK_135_CLOCK_TOO_HIGH           (1 << 1)
+/* Prefer the largest mode at 75 Hz */
+#define EDID_QUIRK_PREFER_LARGE_75              (1 << 2)
+/* Detail timing is in cm not mm */
+#define EDID_QUIRK_DETAILED_IN_CM               (1 << 3)
+/* Detailed timing descriptors have bogus size values, so just take the
+ * maximum size and use that.
+ */
+#define EDID_QUIRK_DETAILED_USE_MAXIMUM_SIZE    (1 << 4)
+/* Monitor forgot to set the first detailed is preferred bit. */
+#define EDID_QUIRK_FIRST_DETAILED_PREFERRED     (1 << 5)
+/* use +hsync +vsync for detailed mode */
+#define EDID_QUIRK_DETAILED_SYNC_PP             (1 << 6)
+
+static struct edid_quirk {
+        char *vendor;
+        int product_id;
+        u32 quirks;
+} edid_quirk_list[] = {
+        /* Acer AL1706 */
+        { "ACR", 44358, EDID_QUIRK_PREFER_LARGE_60 },
+        /* Acer F51 */
+        { "API", 0x7602, EDID_QUIRK_PREFER_LARGE_60 },
+        /* Unknown Acer */
+        { "ACR", 2423, EDID_QUIRK_FIRST_DETAILED_PREFERRED },
+
+        /* Belinea 10 15 55 */
+        { "MAX", 1516, EDID_QUIRK_PREFER_LARGE_60 },
+        { "MAX", 0x77e, EDID_QUIRK_PREFER_LARGE_60 },
+
+        /* Envision Peripherals, Inc. EN-7100e */
+        { "EPI", 59264, EDID_QUIRK_135_CLOCK_TOO_HIGH },
+
+        /* Funai Electronics PM36B */
+        { "FCM", 13600, EDID_QUIRK_PREFER_LARGE_75 |
+          EDID_QUIRK_DETAILED_IN_CM },
+
+        /* LG Philips LCD LP154W01-A5 */
+        { "LPL", 0, EDID_QUIRK_DETAILED_USE_MAXIMUM_SIZE },
+        { "LPL", 0x2a00, EDID_QUIRK_DETAILED_USE_MAXIMUM_SIZE },
+
+        /* Philips 107p5 CRT */
+        { "PHL", 57364, EDID_QUIRK_FIRST_DETAILED_PREFERRED },
+
+        /* Proview AY765C */
+        { "PTS", 765, EDID_QUIRK_FIRST_DETAILED_PREFERRED },
+
+        /* Samsung SyncMaster 205BW.  Note: irony */
+        { "SAM", 541, EDID_QUIRK_DETAILED_SYNC_PP },
+        /* Samsung SyncMaster 22[5-6]BW */
+        { "SAM", 596, EDID_QUIRK_PREFER_LARGE_60 },
+        { "SAM", 638, EDID_QUIRK_PREFER_LARGE_60 },
+};
+
+
+/* Valid EDID header has these bytes */
+static u8 edid_header[] = { 0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00 };
+
+/**
+ * edid_is_valid - sanity check EDID data
+ * @edid: EDID data
+ *
+ * Sanity check the EDID block by looking at the header, the version number
+ * and the checksum.  Return 0 if the EDID doesn't check out, or 1 if it's
+ * valid.
+ */
+static bool edid_is_valid(struct edid *edid)
+{
+        int i;
+        u8 csum = 0;
+        u8 *raw_edid = (u8 *)edid;
+
+        if (memcmp(edid->header, edid_header, sizeof(edid_header)))
+                goto bad;
+        if (edid->version != 1) {
+                DRM_ERROR("EDID has major version %d, instead of 1\n", edid->version);
+                goto bad;
+        }
+        if (edid->revision <= 0 || edid->revision > 3) {
+                DRM_ERROR("EDID has minor version %d, which is not between 0-3\n", edid->revision);
+                goto bad;
+        }
+
+        for (i = 0; i < EDID_LENGTH; i++)
+                csum += raw_edid[i];
+        if (csum) {
+                DRM_ERROR("EDID checksum is invalid, remainder is %d\n", csum);
+                goto bad;
+        }
+
+        return 1;
+
+bad:
+        if (raw_edid) {
+                DRM_ERROR("Raw EDID:\n");
+                print_hex_dump_bytes(KERN_ERR, DUMP_PREFIX_NONE, raw_edid, EDID_LENGTH);
+                printk("\n");
+        }
+        return 0;
+}
+
+/**
+ * edid_vendor - match a string against EDID's obfuscated vendor field
+ * @edid: EDID to match
+ * @vendor: vendor string
+ *
+ * Returns true if @vendor is in @edid, false otherwise
+ */
+static bool edid_vendor(struct edid *edid, char *vendor)
+{
+        char edid_vendor[3];
+
+        edid_vendor[0] = ((edid->mfg_id[0] & 0x7c) >> 2) + '@';
+        edid_vendor[1] = (((edid->mfg_id[0] & 0x3) << 3) |
+                          ((edid->mfg_id[1] & 0xe0) >> 5)) + '@';
+        edid_vendor[2] = (edid->mfg_id[2] & 0x1f) + '@';
+
+        return !strncmp(edid_vendor, vendor, 3);
+}
+
+/**
+ * edid_get_quirks - return quirk flags for a given EDID
+ * @edid: EDID to process
+ *
+ * This tells subsequent routines what fixes they need to apply.
+ */
+static u32 edid_get_quirks(struct edid *edid)
+{
+        struct edid_quirk *quirk;
+        int i;
+
+        for (i = 0; i < ARRAY_SIZE(edid_quirk_list); i++) {
+                quirk = &edid_quirk_list[i];
+
+                if (edid_vendor(edid, quirk->vendor) &&
+                    (EDID_PRODUCT_ID(edid) == quirk->product_id))
+                        return quirk->quirks;
+        }
+
+        return 0;
+}
+
+#define MODE_SIZE(m) ((m)->hdisplay * (m)->vdisplay)
+#define MODE_REFRESH_DIFF(m,r) (abs((m)->vrefresh - target_refresh))
+
+
+/**
+ * edid_fixup_preferred - set preferred modes based on quirk list
+ * @connector: has mode list to fix up
+ * @quirks: quirks list
+ *
+ * Walk the mode list for @connector, clearing the preferred status
+ * on existing modes and setting it anew for the right mode ala @quirks.
+ */
+static void edid_fixup_preferred(struct drm_connector *connector,
+                                 u32 quirks)
+{
+        struct drm_display_mode *t, *cur_mode, *preferred_mode;
+        int target_refresh;
+
+        if (list_empty(&connector->probed_modes))
+                return;
+
+        if (quirks & EDID_QUIRK_PREFER_LARGE_60)
+                target_refresh = 60;
+        if (quirks & EDID_QUIRK_PREFER_LARGE_75)
+                target_refresh = 75;
+
+        preferred_mode = list_first_entry(&connector->probed_modes,
+                                          struct drm_display_mode, head);
+
+        list_for_each_entry_safe(cur_mode, t, &connector->probed_modes, head) {
+                cur_mode->type &= ~DRM_MODE_TYPE_PREFERRED;
+
+                if (cur_mode == preferred_mode)
+                        continue;
+
+                /* Largest mode is preferred */
+                if (MODE_SIZE(cur_mode) > MODE_SIZE(preferred_mode))
+                        preferred_mode = cur_mode;
+
+                /* At a given size, try to get closest to target refresh */
+                if ((MODE_SIZE(cur_mode) == MODE_SIZE(preferred_mode)) &&
+                    MODE_REFRESH_DIFF(cur_mode, target_refresh) <
+                    MODE_REFRESH_DIFF(preferred_mode, target_refresh)) {
+                        preferred_mode = cur_mode;
+                }
+        }
+
+        preferred_mode->type |= DRM_MODE_TYPE_PREFERRED;
+}
+
+/**
+ * drm_mode_std - convert standard mode info (width, height, refresh) into mode
+ * @t: standard timing params
+ *
+ * Take the standard timing params (in this case width, aspect, and refresh)
+ * and convert them into a real mode using CVT.
+ *
+ * Punts for now, but should eventually use the FB layer's CVT based mode
+ * generation code.
+ */
+struct drm_display_mode *drm_mode_std(struct drm_device *dev,
+                                      struct std_timing *t)
+{
+        struct drm_display_mode *mode;
+        int hsize = t->hsize * 8 + 248, vsize;
+
+        mode = drm_mode_create(dev);
+        if (!mode)
+                return NULL;
+
+        if (t->aspect_ratio == 0)
+                vsize = (hsize * 10) / 16;
+        else if (t->aspect_ratio == 1)
+                vsize = (hsize * 3) / 4;
+        else if (t->aspect_ratio == 2)
+                vsize = (hsize * 4) / 5;
+        else
+                vsize = (hsize * 9) / 16;
+
+        drm_mode_set_name(mode);
+
+        return mode;
+}
+
+/**
+ * drm_mode_detailed - create a new mode from an EDID detailed timing section
+ * @dev: DRM device (needed to create new mode)
+ * @edid: EDID block
+ * @timing: EDID detailed timing info
+ * @quirks: quirks to apply
+ *
+ * An EDID detailed timing block contains enough info for us to create and
+ * return a new struct drm_display_mode.
+ */
+static struct drm_display_mode *drm_mode_detailed(struct drm_device *dev,
+                                                  struct edid *edid,
+                                                  struct detailed_timing *timing,
+                                                  u32 quirks)
+{
+        struct drm_display_mode *mode;
+        struct detailed_pixel_timing *pt = &timing->data.pixel_data;
+
+        if (pt->stereo) {
+                printk(KERN_WARNING "stereo mode not supported\n");
+                return NULL;
+        }
+        if (!pt->separate_sync) {
+                printk(KERN_WARNING "integrated sync not supported\n");
+                return NULL;
+        }
+
+        mode = drm_mode_create(dev);
+        if (!mode)
+                return NULL;
+
+        mode->type = DRM_MODE_TYPE_DRIVER;
+
+        if (quirks & EDID_QUIRK_135_CLOCK_TOO_HIGH)
+                timing->pixel_clock = 1088;
+
+        mode->clock = timing->pixel_clock * 10;
+
+        mode->hdisplay = (pt->hactive_hi << 8) | pt->hactive_lo;
+        mode->hsync_start = mode->hdisplay + ((pt->hsync_offset_hi << 8) |
+                                              pt->hsync_offset_lo);
+        mode->hsync_end = mode->hsync_start +
+                ((pt->hsync_pulse_width_hi << 8) |
+                 pt->hsync_pulse_width_lo);
+        mode->htotal = mode->hdisplay + ((pt->hblank_hi << 8) | pt->hblank_lo);
+
+        mode->vdisplay = (pt->vactive_hi << 8) | pt->vactive_lo;
+        mode->vsync_start = mode->vdisplay + ((pt->vsync_offset_hi << 8) |
+                                              pt->vsync_offset_lo);
+        mode->vsync_end = mode->vsync_start +
+                ((pt->vsync_pulse_width_hi << 8) |
+                 pt->vsync_pulse_width_lo);
+        mode->vtotal = mode->vdisplay + ((pt->vblank_hi << 8) | pt->vblank_lo);
+
+        drm_mode_set_name(mode);
+
+        if (pt->interlaced)
+                mode->flags |= DRM_MODE_FLAG_INTERLACE;
+
+        if (quirks & EDID_QUIRK_DETAILED_SYNC_PP) {
+                pt->hsync_positive = 1;
+                pt->vsync_positive = 1;
+        }
+
+        mode->flags |= pt->hsync_positive ? DRM_MODE_FLAG_PHSYNC : DRM_MODE_FLAG_NHSYNC;
+        mode->flags |= pt->vsync_positive ? DRM_MODE_FLAG_PVSYNC : DRM_MODE_FLAG_NVSYNC;
+
+        mode->width_mm = pt->width_mm_lo | (pt->width_mm_hi << 8);
+        mode->height_mm = pt->height_mm_lo | (pt->height_mm_hi << 8);
+
+        if (quirks & EDID_QUIRK_DETAILED_IN_CM) {
+                mode->width_mm *= 10;
+                mode->height_mm *= 10;
+        }
+
+        if (quirks & EDID_QUIRK_DETAILED_USE_MAXIMUM_SIZE) {
+                mode->width_mm = edid->width_cm * 10;
+                mode->height_mm = edid->height_cm * 10;
+        }
+
+        return mode;
+}
+
+/*
+ * Detailed mode info for the EDID "established modes" data to use.
+ */
+static struct drm_display_mode edid_est_modes[] = {
+        { DRM_MODE("800x600", DRM_MODE_TYPE_DRIVER, 40000, 800, 840,
+                   968, 1056, 0, 600, 601, 605, 628, 0,
+                   DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC) }, /* 800x600@60Hz */
+        { DRM_MODE("800x600", DRM_MODE_TYPE_DRIVER, 36000, 800, 824,
+                   896, 1024, 0, 600, 601, 603,  625, 0,
+                   DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC) }, /* 800x600@56Hz */
+        { DRM_MODE("640x480", DRM_MODE_TYPE_DRIVER, 31500, 640, 656,
+                   720, 840, 0, 480, 481, 484, 500, 0,
+                   DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC) }, /* 640x480@75Hz */
+        { DRM_MODE("640x480", DRM_MODE_TYPE_DRIVER, 31500, 640, 664,
+                   704,  832, 0, 480, 489, 491, 520, 0,
+                   DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC) }, /* 640x480@72Hz */
+        { DRM_MODE("640x480", DRM_MODE_TYPE_DRIVER, 30240, 640, 704,
+                   768,  864, 0, 480, 483, 486, 525, 0,
+                   DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC) }, /* 640x480@67Hz */
+        { DRM_MODE("640x480", DRM_MODE_TYPE_DRIVER, 25200, 640, 656,
+                   752, 800, 0, 480, 490, 492, 525, 0,
+                   DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC) }, /* 640x480@60Hz */
+        { DRM_MODE("720x400", DRM_MODE_TYPE_DRIVER, 35500, 720, 738,
+                   846, 900, 0, 400, 421, 423,  449, 0,
+                   DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC) }, /* 720x400@88Hz */
+        { DRM_MODE("720x400", DRM_MODE_TYPE_DRIVER, 28320, 720, 738,
+                   846,  900, 0, 400, 412, 414, 449, 0,
+                   DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_PVSYNC) }, /* 720x400@70Hz */
+        { DRM_MODE("1280x1024", DRM_MODE_TYPE_DRIVER, 135000, 1280, 1296,
+                   1440, 1688, 0, 1024, 1025, 1028, 1066, 0,
+                   DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC) }, /* 1280x1024@75Hz */
+        { DRM_MODE("1024x768", DRM_MODE_TYPE_DRIVER, 78800, 1024, 1040,
+                   1136, 1312, 0,  768, 769, 772, 800, 0,
+                   DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC) }, /* 1024x768@75Hz */
+        { DRM_MODE("1024x768", DRM_MODE_TYPE_DRIVER, 75000, 1024, 1048,
+                   1184, 1328, 0,  768, 771, 777, 806, 0,
+                   DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC) }, /* 1024x768@70Hz */
+        { DRM_MODE("1024x768", DRM_MODE_TYPE_DRIVER, 65000, 1024, 1048,
+                   1184, 1344, 0,  768, 771, 777, 806, 0,
+                   DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC) }, /* 1024x768@60Hz */
+        { DRM_MODE("1024x768", DRM_MODE_TYPE_DRIVER,44900, 1024, 1032,
+                   1208, 1264, 0, 768, 768, 776, 817, 0,
+                   DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC | DRM_MODE_FLAG_INTERLACE) }, /* 1024x768@43Hz */
+        { DRM_MODE("832x624", DRM_MODE_TYPE_DRIVER, 57284, 832, 864,
+                   928, 1152, 0, 624, 625, 628, 667, 0,
+                   DRM_MODE_FLAG_NHSYNC | DRM_MODE_FLAG_NVSYNC) }, /* 832x624@75Hz */
+        { DRM_MODE("800x600", DRM_MODE_TYPE_DRIVER, 49500, 800, 816,
+                   896, 1056, 0, 600, 601, 604,  625, 0,
+                   DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC) }, /* 800x600@75Hz */
+        { DRM_MODE("800x600", DRM_MODE_TYPE_DRIVER, 50000, 800, 856,
+                   976, 1040, 0, 600, 637, 643, 666, 0,
+                   DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC) }, /* 800x600@72Hz */
+        { DRM_MODE("1152x864", DRM_MODE_TYPE_DRIVER, 108000, 1152, 1216,
+                   1344, 1600, 0,  864, 865, 868, 900, 0,
+                   DRM_MODE_FLAG_PHSYNC | DRM_MODE_FLAG_PVSYNC) }, /* 1152x864@75Hz */
+};
+
+#define EDID_EST_TIMINGS 16
+#define EDID_STD_TIMINGS 8
+#define EDID_DETAILED_TIMINGS 4
+
+/**
+ * add_established_modes - get est. modes from EDID and add them
+ * @edid: EDID block to scan
+ *
+ * Each EDID block contains a bitmap of the supported "established modes" list
+ * (defined above).  Tease them out and add them to the global modes list.
+ */
+static int add_established_modes(struct drm_connector *connector, struct edid *edid)
+{
+        struct drm_device *dev = connector->dev;
+        unsigned long est_bits = edid->established_timings.t1 |
+                (edid->established_timings.t2 << 8) |
+                ((edid->established_timings.mfg_rsvd & 0x80) << 9);
+        int i, modes = 0;
+
+        for (i = 0; i <= EDID_EST_TIMINGS; i++)
+                if (est_bits & (1<<i)) {
+                        struct drm_display_mode *newmode;
+                        newmode = drm_mode_duplicate(dev, &edid_est_modes[i]);
+                        if (newmode) {
+                                drm_mode_probed_add(connector, newmode);
+                                modes++;
+                        }
+                }
+
+        return modes;
+}
+
+/**
+ * add_standard_modes - get std. modes from EDID and add them
+ * @edid: EDID block to scan
+ *
+ * Standard modes can be calculated using the CVT standard.  Grab them from
+ * @edid, calculate them, and add them to the list.
+ */
+static int add_standard_modes(struct drm_connector *connector, struct edid *edid)
+{
+        struct drm_device *dev = connector->dev;
+        int i, modes = 0;
+
+        for (i = 0; i < EDID_STD_TIMINGS; i++) {
+                struct std_timing *t = &edid->standard_timings[i];
+                struct drm_display_mode *newmode;
+
+                /* If std timings bytes are 1, 1 it's empty */
+                if (t->hsize == 1 && (t->aspect_ratio | t->vfreq) == 1)
+                        continue;
+
+                newmode = drm_mode_std(dev, &edid->standard_timings[i]);
+                if (newmode) {
+                        drm_mode_probed_add(connector, newmode);
+                        modes++;
+                }
+        }
+
+        return modes;
+}
+
+/**
+ * add_detailed_modes - get detailed mode info from EDID data
+ * @connector: attached connector
+ * @edid: EDID block to scan
+ * @quirks: quirks to apply
+ *
+ * Some of the detailed timing sections may contain mode information.  Grab
+ * it and add it to the list.
+ */
+static int add_detailed_info(struct drm_connector *connector,
+                             struct edid *edid, u32 quirks)
+{
+        struct drm_device *dev = connector->dev;
+        int i, j, modes = 0;
+
+        for (i = 0; i < EDID_DETAILED_TIMINGS; i++) {
+                struct detailed_timing *timing = &edid->detailed_timings[i];
+                struct detailed_non_pixel *data = &timing->data.other_data;
+                struct drm_display_mode *newmode;
+
+                /* EDID up to and including 1.2 may put monitor info here */
+                if (edid->version == 1 && edid->revision < 3)
+                        continue;
+
+                /* Detailed mode timing */
+                if (timing->pixel_clock) {
+                        newmode = drm_mode_detailed(dev, edid, timing, quirks);
+                        if (!newmode)
+                                continue;
+
+                        /* First detailed mode is preferred */
+                        if (i == 0 && edid->preferred_timing)
+                                newmode->type |= DRM_MODE_TYPE_PREFERRED;
+                        drm_mode_probed_add(connector, newmode);
+
+                        modes++;
+                        continue;
+                }
+
+                /* Other timing or info */
+                switch (data->type) {
+                case EDID_DETAIL_MONITOR_SERIAL:
+                        break;
+                case EDID_DETAIL_MONITOR_STRING:
+                        break;
+                case EDID_DETAIL_MONITOR_RANGE:
+                        /* Get monitor range data */
+                        break;
+                case EDID_DETAIL_MONITOR_NAME:
+                        break;
+                case EDID_DETAIL_MONITOR_CPDATA:
+                        break;
+                case EDID_DETAIL_STD_MODES:
+                        /* Five modes per detailed section */
+                        for (j = 0; j < 5; i++) {
+                                struct std_timing *std;
+                                struct drm_display_mode *newmode;
+
+                                std = &data->data.timings[j];
+                                newmode = drm_mode_std(dev, std);
+                                if (newmode) {
+                                        drm_mode_probed_add(connector, newmode);
+                                        modes++;
+                                }
+                        }
+                        break;
+                default:
+                        break;
+                }
+        }
+
+        return modes;
+}
+
+#define DDC_ADDR 0x50
+
+unsigned char *drm_do_probe_ddc_edid(struct i2c_adapter *adapter)
+{
+        unsigned char start = 0x0;
+        unsigned char *buf = kmalloc(EDID_LENGTH, GFP_KERNEL);
+        struct i2c_msg msgs[] = {
+                {
+                        .addr   = DDC_ADDR,
+                        .flags  = 0,
+                        .len    = 1,
+                        .buf    = &start,
+                }, {
+                        .addr   = DDC_ADDR,
+                        .flags  = I2C_M_RD,
+                        .len    = EDID_LENGTH,
+                        .buf    = buf,
+                }
+        };
+
+        if (!buf) {
+                dev_warn(&adapter->dev, "unable to allocate memory for EDID "
+                         "block.\n");
+                return NULL;
+        }
+
+        if (i2c_transfer(adapter, msgs, 2) == 2)
+                return buf;
+
+        dev_info(&adapter->dev, "unable to read EDID block.\n");
+        kfree(buf);
+        return NULL;
+}
+EXPORT_SYMBOL(drm_do_probe_ddc_edid);
+
+static unsigned char *drm_ddc_read(struct i2c_adapter *adapter)
+{
+        struct i2c_algo_bit_data *algo_data = adapter->algo_data;
+        unsigned char *edid = NULL;
+        int i, j;
+
+        algo_data->setscl(algo_data->data, 1);
+
+        for (i = 0; i < 1; i++) {
+                /* For some old monitors we need the
+                 * following process to initialize/stop DDC
+                 */
+                algo_data->setsda(algo_data->data, 1);
+                msleep(13);
+
+                algo_data->setscl(algo_data->data, 1);
+                for (j = 0; j < 5; j++) {
+                        msleep(10);
+                        if (algo_data->getscl(algo_data->data))
+                                break;
+                }
+                if (j == 5)
+                        continue;
+
+                algo_data->setsda(algo_data->data, 0);
+                msleep(15);
+                algo_data->setscl(algo_data->data, 0);
+                msleep(15);
+                algo_data->setsda(algo_data->data, 1);
+                msleep(15);
+
+                /* Do the real work */
+                edid = drm_do_probe_ddc_edid(adapter);
+                algo_data->setsda(algo_data->data, 0);
+                algo_data->setscl(algo_data->data, 0);
+                msleep(15);
+
+                algo_data->setscl(algo_data->data, 1);
+                for (j = 0; j < 10; j++) {
+                        msleep(10);
+                        if (algo_data->getscl(algo_data->data))
+                                break;
+                }
+
+                algo_data->setsda(algo_data->data, 1);
+                msleep(15);
+                algo_data->setscl(algo_data->data, 0);
+                algo_data->setsda(algo_data->data, 0);
+                if (edid)
+                        break;
+        }
+        /* Release the DDC lines when done or the Apple Cinema HD display
+         * will switch off
+         */
+        algo_data->setsda(algo_data->data, 1);
+        algo_data->setscl(algo_data->data, 1);
+
+        return edid;
+}
+
+/**
+ * drm_get_edid - get EDID data, if available
+ * @connector: connector we're probing
+ * @adapter: i2c adapter to use for DDC
+ *
+ * Poke the given connector's i2c channel to grab EDID data if possible.
+ *
+ * Return edid data or NULL if we couldn't find any.
+ */
+struct edid *drm_get_edid(struct drm_connector *connector,
+                          struct i2c_adapter *adapter)
+{
+        struct edid *edid;
+
+        edid = (struct edid *)drm_ddc_read(adapter);
+        if (!edid) {
+                dev_warn(&connector->dev->pdev->dev, "%s: no EDID data\n",
+                         drm_get_connector_name(connector));
+                return NULL;
+        }
+        if (!edid_is_valid(edid)) {
+                dev_warn(&connector->dev->pdev->dev, "%s: EDID invalid.\n",
+                         drm_get_connector_name(connector));
+                kfree(edid);
+                return NULL;
+        }
+
+        connector->display_info.raw_edid = (char *)edid;
+
+        return edid;
+}
+EXPORT_SYMBOL(drm_get_edid);
+
+/**
+ * drm_add_edid_modes - add modes from EDID data, if available
+ * @connector: connector we're probing
+ * @edid: edid data
+ *
+ * Add the specified modes to the connector's mode list.
+ *
+ * Return number of modes added or 0 if we couldn't find any.
+ */
+int drm_add_edid_modes(struct drm_connector *connector, struct edid *edid)
+{
+        int num_modes = 0;
+        u32 quirks;
+
+        if (edid == NULL) {
+                return 0;
+        }
+        if (!edid_is_valid(edid)) {
+                dev_warn(&connector->dev->pdev->dev, "%s: EDID invalid.\n",
+                         drm_get_connector_name(connector));
+                return 0;
+        }
+
+        quirks = edid_get_quirks(edid);
+
+        num_modes += add_established_modes(connector, edid);
+        num_modes += add_standard_modes(connector, edid);
+        num_modes += add_detailed_info(connector, edid, quirks);
+
+        if (quirks & (EDID_QUIRK_PREFER_LARGE_60 | EDID_QUIRK_PREFER_LARGE_75))
+                edid_fixup_preferred(connector, quirks);
+
+        connector->display_info.serration_vsync = edid->serration_vsync;
+        connector->display_info.sync_on_green = edid->sync_on_green;
+        connector->display_info.composite_sync = edid->composite_sync;
+        connector->display_info.separate_syncs = edid->separate_syncs;
+        connector->display_info.blank_to_black = edid->blank_to_black;
+        connector->display_info.video_level = edid->video_level;
+        connector->display_info.digital = edid->digital;
+        connector->display_info.width_mm = edid->width_cm * 10;
+        connector->display_info.height_mm = edid->height_cm * 10;
+        connector->display_info.gamma = edid->gamma;
+        connector->display_info.gtf_supported = edid->default_gtf;
+        connector->display_info.standard_color = edid->standard_color;
+        connector->display_info.display_type = edid->display_type;
+        connector->display_info.active_off_supported = edid->pm_active_off;
+        connector->display_info.suspend_supported = edid->pm_suspend;
+        connector->display_info.standby_supported = edid->pm_standby;
+        connector->display_info.gamma = edid->gamma;
+
+        return num_modes;
+}
+EXPORT_SYMBOL(drm_add_edid_modes);