ASoC: tlv312aic23: unbreak resume

[zen-stable.git] / drivers / gpu / drm / i915 / intel_bios.c

/*
 * Copyright © 2006 Intel Corporation
 *
 * 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:
 *    Eric Anholt <eric@anholt.net>
 *
 */
#include <linux/dmi.h>
#include <drm/drm_dp_helper.h>
#include "drmP.h"
#include "drm.h"
#include "i915_drm.h"
#include "i915_drv.h"
#include "intel_bios.h"

#define SLAVE_ADDR1     0x70
#define SLAVE_ADDR2     0x72

static int panel_type;

static void *
find_section(struct bdb_header *bdb, int section_id)
{
        u8 *base = (u8 *)bdb;
        int index = 0;
        u16 total, current_size;
        u8 current_id;

        /* skip to first section */
        index += bdb->header_size;
        total = bdb->bdb_size;

        /* walk the sections looking for section_id */
        while (index < total) {
                current_id = *(base + index);
                index++;
                current_size = *((u16 *)(base + index));
                index += 2;
                if (current_id == section_id)
                        return base + index;
                index += current_size;
        }

        return NULL;
}

static u16
get_blocksize(void *p)
{
        u16 *block_ptr, block_size;

        block_ptr = (u16 *)((char *)p - 2);
        block_size = *block_ptr;
        return block_size;
}

static void
fill_detail_timing_data(struct drm_display_mode *panel_fixed_mode,
                        const struct lvds_dvo_timing *dvo_timing)
{
        panel_fixed_mode->hdisplay = (dvo_timing->hactive_hi << 8) |
                dvo_timing->hactive_lo;
        panel_fixed_mode->hsync_start = panel_fixed_mode->hdisplay +
                ((dvo_timing->hsync_off_hi << 8) | dvo_timing->hsync_off_lo);
        panel_fixed_mode->hsync_end = panel_fixed_mode->hsync_start +
                dvo_timing->hsync_pulse_width;
        panel_fixed_mode->htotal = panel_fixed_mode->hdisplay +
                ((dvo_timing->hblank_hi << 8) | dvo_timing->hblank_lo);

        panel_fixed_mode->vdisplay = (dvo_timing->vactive_hi << 8) |
                dvo_timing->vactive_lo;
        panel_fixed_mode->vsync_start = panel_fixed_mode->vdisplay +
                dvo_timing->vsync_off;
        panel_fixed_mode->vsync_end = panel_fixed_mode->vsync_start +
                dvo_timing->vsync_pulse_width;
        panel_fixed_mode->vtotal = panel_fixed_mode->vdisplay +
                ((dvo_timing->vblank_hi << 8) | dvo_timing->vblank_lo);
        panel_fixed_mode->clock = dvo_timing->clock * 10;
        panel_fixed_mode->type = DRM_MODE_TYPE_PREFERRED;

        if (dvo_timing->hsync_positive)
                panel_fixed_mode->flags |= DRM_MODE_FLAG_PHSYNC;
        else
                panel_fixed_mode->flags |= DRM_MODE_FLAG_NHSYNC;

        if (dvo_timing->vsync_positive)
                panel_fixed_mode->flags |= DRM_MODE_FLAG_PVSYNC;
        else
                panel_fixed_mode->flags |= DRM_MODE_FLAG_NVSYNC;

        /* Some VBTs have bogus h/vtotal values */
        if (panel_fixed_mode->hsync_end > panel_fixed_mode->htotal)
                panel_fixed_mode->htotal = panel_fixed_mode->hsync_end + 1;
        if (panel_fixed_mode->vsync_end > panel_fixed_mode->vtotal)
                panel_fixed_mode->vtotal = panel_fixed_mode->vsync_end + 1;

        drm_mode_set_name(panel_fixed_mode);
}

static bool
lvds_dvo_timing_equal_size(const struct lvds_dvo_timing *a,
                           const struct lvds_dvo_timing *b)
{
        if (a->hactive_hi != b->hactive_hi ||
            a->hactive_lo != b->hactive_lo)
                return false;

        if (a->hsync_off_hi != b->hsync_off_hi ||
            a->hsync_off_lo != b->hsync_off_lo)
                return false;

        if (a->hsync_pulse_width != b->hsync_pulse_width)
                return false;

        if (a->hblank_hi != b->hblank_hi ||
            a->hblank_lo != b->hblank_lo)
                return false;

        if (a->vactive_hi != b->vactive_hi ||
            a->vactive_lo != b->vactive_lo)
                return false;

        if (a->vsync_off != b->vsync_off)
                return false;

        if (a->vsync_pulse_width != b->vsync_pulse_width)
                return false;

        if (a->vblank_hi != b->vblank_hi ||
            a->vblank_lo != b->vblank_lo)
                return false;

        return true;
}

static const struct lvds_dvo_timing *
get_lvds_dvo_timing(const struct bdb_lvds_lfp_data *lvds_lfp_data,
                    const struct bdb_lvds_lfp_data_ptrs *lvds_lfp_data_ptrs,
                    int index)
{
        /*
         * the size of fp_timing varies on the different platform.
         * So calculate the DVO timing relative offset in LVDS data
         * entry to get the DVO timing entry
         */

        int lfp_data_size =
                lvds_lfp_data_ptrs->ptr[1].dvo_timing_offset -
                lvds_lfp_data_ptrs->ptr[0].dvo_timing_offset;
        int dvo_timing_offset =
                lvds_lfp_data_ptrs->ptr[0].dvo_timing_offset -
                lvds_lfp_data_ptrs->ptr[0].fp_timing_offset;
        char *entry = (char *)lvds_lfp_data->data + lfp_data_size * index;

        return (struct lvds_dvo_timing *)(entry + dvo_timing_offset);
}

/* Try to find integrated panel data */
static void
parse_lfp_panel_data(struct drm_i915_private *dev_priv,
                            struct bdb_header *bdb)
{
        const struct bdb_lvds_options *lvds_options;
        const struct bdb_lvds_lfp_data *lvds_lfp_data;
        const struct bdb_lvds_lfp_data_ptrs *lvds_lfp_data_ptrs;
        const struct lvds_dvo_timing *panel_dvo_timing;
        struct drm_display_mode *panel_fixed_mode;
        int i, downclock;

        lvds_options = find_section(bdb, BDB_LVDS_OPTIONS);
        if (!lvds_options)
                return;

        dev_priv->lvds_dither = lvds_options->pixel_dither;
        if (lvds_options->panel_type == 0xff)
                return;

        panel_type = lvds_options->panel_type;

        lvds_lfp_data = find_section(bdb, BDB_LVDS_LFP_DATA);
        if (!lvds_lfp_data)
                return;

        lvds_lfp_data_ptrs = find_section(bdb, BDB_LVDS_LFP_DATA_PTRS);
        if (!lvds_lfp_data_ptrs)
                return;

        dev_priv->lvds_vbt = 1;

        panel_dvo_timing = get_lvds_dvo_timing(lvds_lfp_data,
                                               lvds_lfp_data_ptrs,
                                               lvds_options->panel_type);

        panel_fixed_mode = kzalloc(sizeof(*panel_fixed_mode), GFP_KERNEL);
        if (!panel_fixed_mode)
                return;

        fill_detail_timing_data(panel_fixed_mode, panel_dvo_timing);

        dev_priv->lfp_lvds_vbt_mode = panel_fixed_mode;

        DRM_DEBUG_KMS("Found panel mode in BIOS VBT tables:\n");
        drm_mode_debug_printmodeline(panel_fixed_mode);

        /*
         * Iterate over the LVDS panel timing info to find the lowest clock
         * for the native resolution.
         */
        downclock = panel_dvo_timing->clock;
        for (i = 0; i < 16; i++) {
                const struct lvds_dvo_timing *dvo_timing;

                dvo_timing = get_lvds_dvo_timing(lvds_lfp_data,
                                                 lvds_lfp_data_ptrs,
                                                 i);
                if (lvds_dvo_timing_equal_size(dvo_timing, panel_dvo_timing) &&
                    dvo_timing->clock < downclock)
                        downclock = dvo_timing->clock;
        }

        if (downclock < panel_dvo_timing->clock && i915_lvds_downclock) {
                dev_priv->lvds_downclock_avail = 1;
                dev_priv->lvds_downclock = downclock * 10;
                DRM_DEBUG_KMS("LVDS downclock is found in VBT. "
                              "Normal Clock %dKHz, downclock %dKHz\n",
                              panel_fixed_mode->clock, 10*downclock);
        }
}

/* Try to find sdvo panel data */
static void
parse_sdvo_panel_data(struct drm_i915_private *dev_priv,
                      struct bdb_header *bdb)
{
        struct lvds_dvo_timing *dvo_timing;
        struct drm_display_mode *panel_fixed_mode;
        int index;

        index = i915_vbt_sdvo_panel_type;
        if (index == -1) {
                struct bdb_sdvo_lvds_options *sdvo_lvds_options;

                sdvo_lvds_options = find_section(bdb, BDB_SDVO_LVDS_OPTIONS);
                if (!sdvo_lvds_options)
                        return;

                index = sdvo_lvds_options->panel_type;
        }

        dvo_timing = find_section(bdb, BDB_SDVO_PANEL_DTDS);
        if (!dvo_timing)
                return;

        panel_fixed_mode = kzalloc(sizeof(*panel_fixed_mode), GFP_KERNEL);
        if (!panel_fixed_mode)
                return;

        fill_detail_timing_data(panel_fixed_mode, dvo_timing + index);

        dev_priv->sdvo_lvds_vbt_mode = panel_fixed_mode;

        DRM_DEBUG_KMS("Found SDVO panel mode in BIOS VBT tables:\n");
        drm_mode_debug_printmodeline(panel_fixed_mode);
}

static int intel_bios_ssc_frequency(struct drm_device *dev,
                                    bool alternate)
{
        switch (INTEL_INFO(dev)->gen) {
        case 2:
                return alternate ? 66 : 48;
        case 3:
        case 4:
                return alternate ? 100 : 96;
        default:
                return alternate ? 100 : 120;
        }
}

static void
parse_general_features(struct drm_i915_private *dev_priv,
                       struct bdb_header *bdb)
{
        struct drm_device *dev = dev_priv->dev;
        struct bdb_general_features *general;

        general = find_section(bdb, BDB_GENERAL_FEATURES);
        if (general) {
                dev_priv->int_tv_support = general->int_tv_support;
                dev_priv->int_crt_support = general->int_crt_support;
                dev_priv->lvds_use_ssc = general->enable_ssc;
                dev_priv->lvds_ssc_freq =
                        intel_bios_ssc_frequency(dev, general->ssc_freq);
                dev_priv->display_clock_mode = general->display_clock_mode;
                DRM_DEBUG_KMS("BDB_GENERAL_FEATURES int_tv_support %d int_crt_support %d lvds_use_ssc %d lvds_ssc_freq %d display_clock_mode %d\n",
                              dev_priv->int_tv_support,
                              dev_priv->int_crt_support,
                              dev_priv->lvds_use_ssc,
                              dev_priv->lvds_ssc_freq,
                              dev_priv->display_clock_mode);
        }
}

static void
parse_general_definitions(struct drm_i915_private *dev_priv,
                          struct bdb_header *bdb)
{
        struct bdb_general_definitions *general;

        general = find_section(bdb, BDB_GENERAL_DEFINITIONS);
        if (general) {
                u16 block_size = get_blocksize(general);
                if (block_size >= sizeof(*general)) {
                        int bus_pin = general->crt_ddc_gmbus_pin;
                        DRM_DEBUG_KMS("crt_ddc_bus_pin: %d\n", bus_pin);
                        if (bus_pin >= 1 && bus_pin <= 6)
                                dev_priv->crt_ddc_pin = bus_pin;
                } else {
                        DRM_DEBUG_KMS("BDB_GD too small (%d). Invalid.\n",
                                  block_size);
                }
        }
}

static void
parse_sdvo_device_mapping(struct drm_i915_private *dev_priv,
                          struct bdb_header *bdb)
{
        struct sdvo_device_mapping *p_mapping;
        struct bdb_general_definitions *p_defs;
        struct child_device_config *p_child;
        int i, child_device_num, count;
        u16     block_size;

        p_defs = find_section(bdb, BDB_GENERAL_DEFINITIONS);
        if (!p_defs) {
                DRM_DEBUG_KMS("No general definition block is found, unable to construct sdvo mapping.\n");
                return;
        }
        /* judge whether the size of child device meets the requirements.
         * If the child device size obtained from general definition block
         * is different with sizeof(struct child_device_config), skip the
         * parsing of sdvo device info
         */
        if (p_defs->child_dev_size != sizeof(*p_child)) {
                /* different child dev size . Ignore it */
                DRM_DEBUG_KMS("different child size is found. Invalid.\n");
                return;
        }
        /* get the block size of general definitions */
        block_size = get_blocksize(p_defs);
        /* get the number of child device */
        child_device_num = (block_size - sizeof(*p_defs)) /
                                sizeof(*p_child);
        count = 0;
        for (i = 0; i < child_device_num; i++) {
                p_child = &(p_defs->devices[i]);
                if (!p_child->device_type) {
                        /* skip the device block if device type is invalid */
                        continue;
                }
                if (p_child->slave_addr != SLAVE_ADDR1 &&
                        p_child->slave_addr != SLAVE_ADDR2) {
                        /*
                         * If the slave address is neither 0x70 nor 0x72,
                         * it is not a SDVO device. Skip it.
                         */
                        continue;
                }
                if (p_child->dvo_port != DEVICE_PORT_DVOB &&
                        p_child->dvo_port != DEVICE_PORT_DVOC) {
                        /* skip the incorrect SDVO port */
                        DRM_DEBUG_KMS("Incorrect SDVO port. Skip it\n");
                        continue;
                }
                DRM_DEBUG_KMS("the SDVO device with slave addr %2x is found on"
                                " %s port\n",
                                p_child->slave_addr,
                                (p_child->dvo_port == DEVICE_PORT_DVOB) ?
                                        "SDVOB" : "SDVOC");
                p_mapping = &(dev_priv->sdvo_mappings[p_child->dvo_port - 1]);
                if (!p_mapping->initialized) {
                        p_mapping->dvo_port = p_child->dvo_port;
                        p_mapping->slave_addr = p_child->slave_addr;
                        p_mapping->dvo_wiring = p_child->dvo_wiring;
                        p_mapping->ddc_pin = p_child->ddc_pin;
                        p_mapping->i2c_pin = p_child->i2c_pin;
                        p_mapping->initialized = 1;
                        DRM_DEBUG_KMS("SDVO device: dvo=%x, addr=%x, wiring=%d, ddc_pin=%d, i2c_pin=%d\n",
                                      p_mapping->dvo_port,
                                      p_mapping->slave_addr,
                                      p_mapping->dvo_wiring,
                                      p_mapping->ddc_pin,
                                      p_mapping->i2c_pin);
                } else {
                        DRM_DEBUG_KMS("Maybe one SDVO port is shared by "
                                         "two SDVO device.\n");
                }
                if (p_child->slave2_addr) {
                        /* Maybe this is a SDVO device with multiple inputs */
                        /* And the mapping info is not added */
                        DRM_DEBUG_KMS("there exists the slave2_addr. Maybe this"
                                " is a SDVO device with multiple inputs.\n");
                }
                count++;
        }

        if (!count) {
                /* No SDVO device info is found */
                DRM_DEBUG_KMS("No SDVO device info is found in VBT\n");
        }
        return;
}

static void
parse_driver_features(struct drm_i915_private *dev_priv,
                       struct bdb_header *bdb)
{
        struct drm_device *dev = dev_priv->dev;
        struct bdb_driver_features *driver;

        driver = find_section(bdb, BDB_DRIVER_FEATURES);
        if (!driver)
                return;

        if (SUPPORTS_EDP(dev) &&
            driver->lvds_config == BDB_DRIVER_FEATURE_EDP)
                dev_priv->edp.support = 1;

        if (driver->dual_frequency)
                dev_priv->render_reclock_avail = true;
}

static void
parse_edp(struct drm_i915_private *dev_priv, struct bdb_header *bdb)
{
        struct bdb_edp *edp;
        struct edp_power_seq *edp_pps;
        struct edp_link_params *edp_link_params;

        edp = find_section(bdb, BDB_EDP);
        if (!edp) {
                if (SUPPORTS_EDP(dev_priv->dev) && dev_priv->edp.support) {
                        DRM_DEBUG_KMS("No eDP BDB found but eDP panel "
                                      "supported, assume %dbpp panel color "
                                      "depth.\n",
                                      dev_priv->edp.bpp);
                }
                return;
        }

        switch ((edp->color_depth >> (panel_type * 2)) & 3) {
        case EDP_18BPP:
                dev_priv->edp.bpp = 18;
                break;
        case EDP_24BPP:
                dev_priv->edp.bpp = 24;
                break;
        case EDP_30BPP:
                dev_priv->edp.bpp = 30;
                break;
        }

        /* Get the eDP sequencing and link info */
        edp_pps = &edp->power_seqs[panel_type];
        edp_link_params = &edp->link_params[panel_type];

        dev_priv->edp.pps = *edp_pps;

        dev_priv->edp.rate = edp_link_params->rate ? DP_LINK_BW_2_7 :
                DP_LINK_BW_1_62;
        switch (edp_link_params->lanes) {
        case 0:
                dev_priv->edp.lanes = 1;
                break;
        case 1:
                dev_priv->edp.lanes = 2;
                break;
        case 3:
        default:
                dev_priv->edp.lanes = 4;
                break;
        }
        switch (edp_link_params->preemphasis) {
        case 0:
                dev_priv->edp.preemphasis = DP_TRAIN_PRE_EMPHASIS_0;
                break;
        case 1:
                dev_priv->edp.preemphasis = DP_TRAIN_PRE_EMPHASIS_3_5;
                break;
        case 2:
                dev_priv->edp.preemphasis = DP_TRAIN_PRE_EMPHASIS_6;
                break;
        case 3:
                dev_priv->edp.preemphasis = DP_TRAIN_PRE_EMPHASIS_9_5;
                break;
        }
        switch (edp_link_params->vswing) {
        case 0:
                dev_priv->edp.vswing = DP_TRAIN_VOLTAGE_SWING_400;
                break;
        case 1:
                dev_priv->edp.vswing = DP_TRAIN_VOLTAGE_SWING_600;
                break;
        case 2:
                dev_priv->edp.vswing = DP_TRAIN_VOLTAGE_SWING_800;
                break;
        case 3:
                dev_priv->edp.vswing = DP_TRAIN_VOLTAGE_SWING_1200;
                break;
        }
}

static void
parse_device_mapping(struct drm_i915_private *dev_priv,
                       struct bdb_header *bdb)
{
        struct bdb_general_definitions *p_defs;
        struct child_device_config *p_child, *child_dev_ptr;
        int i, child_device_num, count;
        u16     block_size;

        p_defs = find_section(bdb, BDB_GENERAL_DEFINITIONS);
        if (!p_defs) {
                DRM_DEBUG_KMS("No general definition block is found, no devices defined.\n");
                return;
        }
        /* judge whether the size of child device meets the requirements.
         * If the child device size obtained from general definition block
         * is different with sizeof(struct child_device_config), skip the
         * parsing of sdvo device info
         */
        if (p_defs->child_dev_size != sizeof(*p_child)) {
                /* different child dev size . Ignore it */
                DRM_DEBUG_KMS("different child size is found. Invalid.\n");
                return;
        }
        /* get the block size of general definitions */
        block_size = get_blocksize(p_defs);
        /* get the number of child device */
        child_device_num = (block_size - sizeof(*p_defs)) /
                                sizeof(*p_child);
        count = 0;
        /* get the number of child device that is present */
        for (i = 0; i < child_device_num; i++) {
                p_child = &(p_defs->devices[i]);
                if (!p_child->device_type) {
                        /* skip the device block if device type is invalid */
                        continue;
                }
                count++;
        }
        if (!count) {
                DRM_DEBUG_KMS("no child dev is parsed from VBT\n");
                return;
        }
        dev_priv->child_dev = kzalloc(sizeof(*p_child) * count, GFP_KERNEL);
        if (!dev_priv->child_dev) {
                DRM_DEBUG_KMS("No memory space for child device\n");
                return;
        }

        dev_priv->child_dev_num = count;
        count = 0;
        for (i = 0; i < child_device_num; i++) {
                p_child = &(p_defs->devices[i]);
                if (!p_child->device_type) {
                        /* skip the device block if device type is invalid */
                        continue;
                }
                child_dev_ptr = dev_priv->child_dev + count;
                count++;
                memcpy((void *)child_dev_ptr, (void *)p_child,
                                        sizeof(*p_child));
        }
        return;
}

static void
init_vbt_defaults(struct drm_i915_private *dev_priv)
{
        struct drm_device *dev = dev_priv->dev;

        dev_priv->crt_ddc_pin = GMBUS_PORT_VGADDC;

        /* LFP panel data */
        dev_priv->lvds_dither = 1;
        dev_priv->lvds_vbt = 0;

        /* SDVO panel data */
        dev_priv->sdvo_lvds_vbt_mode = NULL;

        /* general features */
        dev_priv->int_tv_support = 1;
        dev_priv->int_crt_support = 1;

        /* Default to using SSC */
        dev_priv->lvds_use_ssc = 1;
        dev_priv->lvds_ssc_freq = intel_bios_ssc_frequency(dev, 1);
        DRM_DEBUG_KMS("Set default to SSC at %dMHz\n", dev_priv->lvds_ssc_freq);

        /* eDP data */
        dev_priv->edp.bpp = 18;
}

static int __init intel_no_opregion_vbt_callback(const struct dmi_system_id *id)
{
        DRM_DEBUG_KMS("Falling back to manually reading VBT from "
                      "VBIOS ROM for %s\n",
                      id->ident);
        return 1;
}

static const struct dmi_system_id intel_no_opregion_vbt[] = {
        {
                .callback = intel_no_opregion_vbt_callback,
                .ident = "ThinkCentre A57",
                .matches = {
                        DMI_MATCH(DMI_SYS_VENDOR, "LENOVO"),
                        DMI_MATCH(DMI_PRODUCT_NAME, "97027RG"),
                },
        },
        { }
};

/**
 * intel_parse_bios - find VBT and initialize settings from the BIOS
 * @dev: DRM device
 *
 * Loads the Video BIOS and checks that the VBT exists.  Sets scratch registers
 * to appropriate values.
 *
 * Returns 0 on success, nonzero on failure.
 */
bool
intel_parse_bios(struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = dev->dev_private;
        struct pci_dev *pdev = dev->pdev;
        struct bdb_header *bdb = NULL;
        u8 __iomem *bios = NULL;

        init_vbt_defaults(dev_priv);

        /* XXX Should this validation be moved to intel_opregion.c? */
        if (!dmi_check_system(intel_no_opregion_vbt) && dev_priv->opregion.vbt) {
                struct vbt_header *vbt = dev_priv->opregion.vbt;
                if (memcmp(vbt->signature, "$VBT", 4) == 0) {
                        DRM_DEBUG_KMS("Using VBT from OpRegion: %20s\n",
                                         vbt->signature);
                        bdb = (struct bdb_header *)((char *)vbt + vbt->bdb_offset);
                } else
                        dev_priv->opregion.vbt = NULL;
        }

        if (bdb == NULL) {
                struct vbt_header *vbt = NULL;
                size_t size;
                int i;

                bios = pci_map_rom(pdev, &size);
                if (!bios)
                        return -1;

                /* Scour memory looking for the VBT signature */
                for (i = 0; i + 4 < size; i++) {
                        if (!memcmp(bios + i, "$VBT", 4)) {
                                vbt = (struct vbt_header *)(bios + i);
                                break;
                        }
                }

                if (!vbt) {
                        DRM_ERROR("VBT signature missing\n");
                        pci_unmap_rom(pdev, bios);
                        return -1;
                }

                bdb = (struct bdb_header *)(bios + i + vbt->bdb_offset);
        }

        /* Grab useful general definitions */
        parse_general_features(dev_priv, bdb);
        parse_general_definitions(dev_priv, bdb);
        parse_lfp_panel_data(dev_priv, bdb);
        parse_sdvo_panel_data(dev_priv, bdb);
        parse_sdvo_device_mapping(dev_priv, bdb);
        parse_device_mapping(dev_priv, bdb);
        parse_driver_features(dev_priv, bdb);
        parse_edp(dev_priv, bdb);

        if (bios)
                pci_unmap_rom(pdev, bios);

        return 0;
}

/* Ensure that vital registers have been initialised, even if the BIOS
 * is absent or just failing to do its job.
 */
void intel_setup_bios(struct drm_device *dev)
{
        struct drm_i915_private *dev_priv = dev->dev_private;

         /* Set the Panel Power On/Off timings if uninitialized. */
        if ((I915_READ(PP_ON_DELAYS) == 0) && (I915_READ(PP_OFF_DELAYS) == 0)) {
                /* Set T2 to 40ms and T5 to 200ms */
                I915_WRITE(PP_ON_DELAYS, 0x019007d0);

                /* Set T3 to 35ms and Tx to 200ms */
                I915_WRITE(PP_OFF_DELAYS, 0x015e07d0);
        }
}