drivers/gpu/drm/i915/intel_bios.c - kernel/msm - Gitiles

 /*
  * 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 "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 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 void
 fill_detail_timing_data(struct drm_display_mode *panel_fixed_mode,
 			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;

 	/* 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);
 }

 /* Try to find integrated panel data */
 static void
 parse_lfp_panel_data(struct drm_i915_private *dev_priv,
 			    struct bdb_header *bdb)
 {
 	struct bdb_lvds_options *lvds_options;
 	struct bdb_lvds_lfp_data *lvds_lfp_data;
 	struct bdb_lvds_lfp_data_ptrs *lvds_lfp_data_ptrs;
 	struct bdb_lvds_lfp_data_entry *entry;
 	struct lvds_dvo_timing *dvo_timing;
 	struct drm_display_mode *panel_fixed_mode;
 	int lfp_data_size, dvo_timing_offset;

 	/* Defaults if we can't find VBT info */
 	dev_priv->lvds_dither = 0;
 	dev_priv->lvds_vbt = 0;

 	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;

 	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;

 	lfp_data_size = lvds_lfp_data_ptrs->ptr[1].dvo_timing_offset -
 		lvds_lfp_data_ptrs->ptr[0].dvo_timing_offset;
 	entry = (struct bdb_lvds_lfp_data_entry *)
 		((uint8_t *)lvds_lfp_data->data + (lfp_data_size *
 						   lvds_options->panel_type));
 	dvo_timing_offset = lvds_lfp_data_ptrs->ptr[0].dvo_timing_offset -
 		lvds_lfp_data_ptrs->ptr[0].fp_timing_offset;

 	/*
 	 * 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
 	 */
 	dvo_timing = (struct lvds_dvo_timing *)
 			((unsigned char *)entry + dvo_timing_offset);

 	panel_fixed_mode = kzalloc(sizeof(*panel_fixed_mode), GFP_KERNEL);

 	fill_detail_timing_data(panel_fixed_mode, dvo_timing);

 	dev_priv->lfp_lvds_vbt_mode = panel_fixed_mode;

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

 	return;
 }

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

 	dev_priv->sdvo_lvds_vbt_mode = NULL;

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

 	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 + sdvo_lvds_options->panel_type);

 	dev_priv->sdvo_lvds_vbt_mode = panel_fixed_mode;

 	return;
 }

 static void
 parse_general_features(struct drm_i915_private *dev_priv,
 		       struct bdb_header *bdb)
 {
 	struct bdb_general_features *general;

 	/* Set sensible defaults in case we can't find the general block */
 	dev_priv->int_tv_support = 1;
 	dev_priv->int_crt_support = 1;

 	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;

 		if (dev_priv->lvds_use_ssc) {
 			if (IS_I85X(dev_priv->dev))
 				dev_priv->lvds_ssc_freq =
 					general->ssc_freq ? 66 : 48;
 			else
 				dev_priv->lvds_ssc_freq =
 					general->ssc_freq ? 100 : 96;
 		}
 	}
 }

 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, *block_ptr;

 	p_defs = find_section(bdb, BDB_GENERAL_DEFINITIONS);
 	if (!p_defs) {
 		DRM_DEBUG("No general definition block is found\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("different child size is found. Invalid.\n");
 		return;
 	}
 	/* get the block size of general definitions */
 	block_ptr = (u16 *)((char *)p_defs - 2);
 	block_size = *block_ptr;
 	/* 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("Incorrect SDVO port. Skip it \n");
 			continue;
 		}
 		DRM_DEBUG("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->initialized = 1;
 		} else {
 			DRM_DEBUG("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("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("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;

 	/* set default for chips without eDP */
 	if (!SUPPORTS_EDP(dev)) {
 		dev_priv->edp_support = 0;
 		return;
 	}

 	driver = find_section(bdb, BDB_DRIVER_FEATURES);
 	if (driver && driver->lvds_config == BDB_DRIVER_FEATURE_EDP)
 		dev_priv->edp_support = 1;
 }

 /**
  * intel_init_bios - initialize VBIOS settings & find VBT
  * @dev: DRM device
  *
  * Loads the Video BIOS and checks that the VBT exists.  Sets scratch registers
  * to appropriate values.
  *
  * VBT existence is a sanity check that is relied on by other i830_bios.c code.
  * Note that it would be better to use a BIOS call to get the VBT, as BIOSes may
  * feed an updated VBT back through that, compared to what we'll fetch using
  * this method of groping around in the BIOS data.
  *
  * Returns 0 on success, nonzero on failure.
  */
 bool
 intel_init_bios(struct drm_device *dev)
 {
 	struct drm_i915_private *dev_priv = dev->dev_private;
 	struct pci_dev *pdev = dev->pdev;
 	struct vbt_header *vbt = NULL;
 	struct bdb_header *bdb;
 	u8 __iomem *bios;
 	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_lfp_panel_data(dev_priv, bdb);
 	parse_sdvo_panel_data(dev_priv, bdb);
 	parse_sdvo_device_mapping(dev_priv, bdb);
 	parse_driver_features(dev_priv, bdb);

 	pci_unmap_rom(pdev, bios);

 	return 0;
 }
	/*
	* 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 "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 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 void
	fill_detail_timing_data(struct drm_display_mode *panel_fixed_mode,
	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;

	/* 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);
	}

	/* Try to find integrated panel data */
	static void
	parse_lfp_panel_data(struct drm_i915_private *dev_priv,
	struct bdb_header *bdb)
	{
	struct bdb_lvds_options *lvds_options;
	struct bdb_lvds_lfp_data *lvds_lfp_data;
	struct bdb_lvds_lfp_data_ptrs *lvds_lfp_data_ptrs;
	struct bdb_lvds_lfp_data_entry *entry;
	struct lvds_dvo_timing *dvo_timing;
	struct drm_display_mode *panel_fixed_mode;
	int lfp_data_size, dvo_timing_offset;

	/* Defaults if we can't find VBT info */
	dev_priv->lvds_dither = 0;
	dev_priv->lvds_vbt = 0;

	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;

	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;

	lfp_data_size = lvds_lfp_data_ptrs->ptr[1].dvo_timing_offset -
	lvds_lfp_data_ptrs->ptr[0].dvo_timing_offset;
	entry = (struct bdb_lvds_lfp_data_entry *)
	((uint8_t )lvds_lfp_data->data + (lfp_data_size
	lvds_options->panel_type));
	dvo_timing_offset = lvds_lfp_data_ptrs->ptr[0].dvo_timing_offset -
	lvds_lfp_data_ptrs->ptr[0].fp_timing_offset;

	/*
	* 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
	*/
	dvo_timing = (struct lvds_dvo_timing *)
	((unsigned char *)entry + dvo_timing_offset);

	panel_fixed_mode = kzalloc(sizeof(*panel_fixed_mode), GFP_KERNEL);

	fill_detail_timing_data(panel_fixed_mode, dvo_timing);

	dev_priv->lfp_lvds_vbt_mode = panel_fixed_mode;

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

	return;
	}

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

	dev_priv->sdvo_lvds_vbt_mode = NULL;

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

	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 + sdvo_lvds_options->panel_type);

	dev_priv->sdvo_lvds_vbt_mode = panel_fixed_mode;

	return;
	}

	static void
	parse_general_features(struct drm_i915_private *dev_priv,
	struct bdb_header *bdb)
	{
	struct bdb_general_features *general;

	/* Set sensible defaults in case we can't find the general block */
	dev_priv->int_tv_support = 1;
	dev_priv->int_crt_support = 1;

	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;

	if (dev_priv->lvds_use_ssc) {
	if (IS_I85X(dev_priv->dev))
	dev_priv->lvds_ssc_freq =
	general->ssc_freq ? 66 : 48;
	else
	dev_priv->lvds_ssc_freq =
	general->ssc_freq ? 100 : 96;
	}
	}
	}

	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, *block_ptr;

	p_defs = find_section(bdb, BDB_GENERAL_DEFINITIONS);
	if (!p_defs) {
	DRM_DEBUG("No general definition block is found\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("different child size is found. Invalid.\n");
	return;
	}
	/* get the block size of general definitions */
	block_ptr = (u16 )((char )p_defs - 2);
	block_size = *block_ptr;
	/* 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("Incorrect SDVO port. Skip it \n");
	continue;
	}
	DRM_DEBUG("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->initialized = 1;
	} else {
	DRM_DEBUG("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("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("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;

	/* set default for chips without eDP */
	if (!SUPPORTS_EDP(dev)) {
	dev_priv->edp_support = 0;
	return;
	}

	driver = find_section(bdb, BDB_DRIVER_FEATURES);
	if (driver && driver->lvds_config == BDB_DRIVER_FEATURE_EDP)
	dev_priv->edp_support = 1;
	}

	/**
	* intel_init_bios - initialize VBIOS settings & find VBT
	* @dev: DRM device
	*
	* Loads the Video BIOS and checks that the VBT exists. Sets scratch registers
	* to appropriate values.
	*
	* VBT existence is a sanity check that is relied on by other i830_bios.c code.
	* Note that it would be better to use a BIOS call to get the VBT, as BIOSes may
	* feed an updated VBT back through that, compared to what we'll fetch using
	* this method of groping around in the BIOS data.
	*
	* Returns 0 on success, nonzero on failure.
	*/
	bool
	intel_init_bios(struct drm_device *dev)
	{
	struct drm_i915_private *dev_priv = dev->dev_private;
	struct pci_dev *pdev = dev->pdev;
	struct vbt_header *vbt = NULL;
	struct bdb_header *bdb;
	u8 __iomem *bios;
	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_lfp_panel_data(dev_priv, bdb);
	parse_sdvo_panel_data(dev_priv, bdb);
	parse_sdvo_device_mapping(dev_priv, bdb);
	parse_driver_features(dev_priv, bdb);

	pci_unmap_rom(pdev, bios);

	return 0;
	}