text: /*
   * Copyright (c) 2006 Luc Verhaegen (quirks list)
   * Copyright (c) 2007-2008 Intel Corporation
   *   Jesse Barnes <jesse.barnes@intel.com>
   * Copyright 2010 Red Hat, Inc.
   *
   * 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/slab.h>
  #include <linux/i2c.h>
  #include <linux/module.h>
  #include "drmP.h"
  #include "drm_edid.h"
  #include "drm_edid_modes.h"
  
  #define version_greater(edid, maj, min) \
  	(((edid)->version > (maj)) || \
  	 ((edid)->version == (maj) && (edid)->revision > (min)))
  
  #define EDID_EST_TIMINGS 16
  #define EDID_STD_TIMINGS 8
  #define EDID_DETAILED_TIMINGS 4
  
  /*
   * 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)
  /* Force reduced-blanking timings for detailed modes */
  #define EDID_QUIRK_FORCE_REDUCED_BLANKING	(1 << 7)
  
  struct detailed_mode_closure {
  	struct drm_connector *connector;
  	struct edid *edid;
  	bool preferred;
  	u32 quirks;
  	int modes;
  };
  
  #define LEVEL_DMT	0
  #define LEVEL_GTF	1
  #define LEVEL_GTF2	2
  #define LEVEL_CVT	3
  
  static struct edid_quirk {
  	char vendor[4];
  	int product_id;
  	u32 quirks;
  } edid_quirk_list[] = {
  	/* ASUS VW222S */
  	{ "ACI", 0x22a2, EDID_QUIRK_FORCE_REDUCED_BLANKING },
  
  	/* 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 },
  	/* Envision EN2028 */
  	{ "EPI", 8232, EDID_QUIRK_PREFER_LARGE_60 },
  
  	/* 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 },
  
  	/* ViewSonic VA2026w */
  	{ "VSC", 5020, EDID_QUIRK_FORCE_REDUCED_BLANKING },
  };
  
  /*** DDC fetch and block validation ***/
  
  static const u8 edid_header[] = {
  	0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00
  };
  
   /*
   * Sanity check the header of the base EDID block.  Return 8 if the header
   * is perfect, down to 0 if it's totally wrong.
   */
  int drm_edid_header_is_valid(const u8 *raw_edid)
  {
  	int i, score = 0;
  
  	for (i = 0; i < sizeof(edid_header); i++)
  		if (raw_edid[i] == edid_header[i])
  			score++;
  
  	return score;
  }
  EXPORT_SYMBOL(drm_edid_header_is_valid);
  
  static int edid_fixup __read_mostly = 6;
  module_param_named(edid_fixup, edid_fixup, int, 0400);
  MODULE_PARM_DESC(edid_fixup,
  		 "Minimum number of valid EDID header bytes (0-8, default 6)");
  
  /*
   * Sanity check the EDID block (base or extension).  Return 0 if the block
   * doesn't check out, or 1 if it's valid.
   */
  bool drm_edid_block_valid(u8 *raw_edid, int block)
  {
  	int i;
  	u8 csum = 0;
  	struct edid *edid = (struct edid *)raw_edid;
  
  	if (edid_fixup > 8 || edid_fixup < 0)
  		edid_fixup = 6;
  
  	if (block == 0) {
  		int score = drm_edid_header_is_valid(raw_edid);
  		if (score == 8) ;
  		else if (score >= edid_fixup) {
  			DRM_DEBUG("Fixing EDID header, your hardware may be failing\n");
  			memcpy(raw_edid, edid_header, sizeof(edid_header));
  		} else {
  			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);
  
  		/* allow CEA to slide through, switches mangle this */
  		if (raw_edid[0] != 0x02)
  			goto bad;
  	}
  
  	/* per-block-type checks */
  	switch (raw_edid[0]) {
  	case 0: /* base */
  		if (edid->version != 1) {
  			DRM_ERROR("EDID has major version %d, instead of 1\n", edid->version);
  			goto bad;
  		}
  
  		if (edid->revision > 4)
  			DRM_DEBUG("EDID minor > 4, assuming backward compatibility\n");
  		break;
  
  	default:
  		break;
  	}
  
  	return 1;
  
  bad:
  	if (raw_edid) {
  		printk(KERN_ERR "Raw EDID:\n");
  		print_hex_dump(KERN_ERR, " \t", DUMP_PREFIX_NONE, 16, 1,
  			       raw_edid, EDID_LENGTH, false);
  	}
  	return 0;
  }
  EXPORT_SYMBOL(drm_edid_block_valid);
  
  /**
   * drm_edid_is_valid - sanity check EDID data
   * @edid: EDID data
   *
   * Sanity-check an entire EDID record (including extensions)
   */
  bool drm_edid_is_valid(struct edid *edid)
  {
  	int i;
  	u8 *raw = (u8 *)edid;
  
  	if (!edid)
  		return false;
  
  	for (i = 0; i <= edid->extensions; i++)
  		if (!drm_edid_block_valid(raw + i * EDID_LENGTH, i))
  			return false;
  
  	return true;
  }
  EXPORT_SYMBOL(drm_edid_is_valid);
  
  #define DDC_SEGMENT_ADDR 0x30
  /**
   * Get EDID information via I2C.
   *
   * \param adapter : i2c device adaptor
   * \param buf     : EDID data buffer to be filled
   * \param len     : EDID data buffer length
   * \return 0 on success or -1 on failure.
   *
   * Try to fetch EDID information by calling i2c driver function.
   */
  static int
  drm_do_probe_ddc_edid(struct i2c_adapter *adapter, unsigned char *buf,
  		      int block, int len)
  {
  	unsigned char start = block * EDID_LENGTH;
  	int ret, retries = 5;
  
  	/* The core i2c driver will automatically retry the transfer if the
  	 * adapter reports EAGAIN. However, we find that bit-banging transfers
  	 * are susceptible to errors under a heavily loaded machine and
  	 * generate spurious NAKs and timeouts. Retrying the transfer
  	 * of the individual block a few times seems to overcome this.
  	 */
  	do {
  		struct i2c_msg msgs[] = {
  			{
  				.addr	= DDC_ADDR,
  				.flags	= 0,
  				.len	= 1,
  				.buf	= &start,
  			}, {
  				.addr	= DDC_ADDR,
  				.flags	= I2C_M_RD,
  				.len	= len,
  				.buf	= buf,
  			}
  		};
  		ret = i2c_transfer(adapter, msgs, 2);
  		if (ret == -ENXIO) {
  			DRM_DEBUG_KMS("drm: skipping non-existent adapter %s\n",
  					adapter->name);
  			break;
  		}
  	} while (ret != 2 && --retries);
  
  	return ret == 2 ? 0 : -1;
  }
  
  static bool drm_edid_is_zero(u8 *in_edid, int length)
  {
  	int i;
  	u32 *raw_edid = (u32 *)in_edid;
  
  	for (i = 0; i < length / 4; i++)
  		if (*(raw_edid + i) != 0)
  			return false;
  	return true;
  }
  
  static u8 *
  drm_do_get_edid(struct drm_connector *connector, struct i2c_adapter *adapter)
  {
  	int i, j = 0, valid_extensions = 0;
  	u8 *block, *new;
  
  	if ((block = kmalloc(EDID_LENGTH, GFP_KERNEL)) == NULL)
  		return NULL;
  
  	/* base block fetch */
  	for (i = 0; i < 4; i++) {
  		if (drm_do_probe_ddc_edid(adapter, block, 0, EDID_LENGTH))
  			goto out;
  		if (drm_edid_block_valid(block, 0))
  			break;
  		if (i == 0 && drm_edid_is_zero(block, EDID_LENGTH)) {
  			connector->null_edid_counter++;
  			goto carp;
  		}
  	}
  	if (i == 4)
  		goto carp;
  
  	/* if there's no extensions, we're done */
  	if (block[0x7e] == 0)
  		return block;
  
  	new = krealloc(block, (block[0x7e] + 1) * EDID_LENGTH, GFP_KERNEL);
  	if (!new)
  		goto out;
  	block = new;
  
  	for (j = 1; j <= block[0x7e]; j++) {
  		for (i = 0; i < 4; i++) {
  			if (drm_do_probe_ddc_edid(adapter,
  				  block + (valid_extensions + 1) * EDID_LENGTH,
  				  j, EDID_LENGTH))
  				goto out;
  			if (drm_edid_block_valid(block + (valid_extensions + 1) * EDID_LENGTH, j)) {
  				valid_extensions++;
  				break;
  			}
  		}
  		if (i == 4)
  			dev_warn(connector->dev->dev,
  			 "%s: Ignoring invalid EDID block %d.\n",
  			 drm_get_connector_name(connector), j);
  	}
  
  	if (valid_extensions != block[0x7e]) {
  		block[EDID_LENGTH-1] += block[0x7e] - valid_extensions;
  		block[0x7e] = valid_extensions;
  		new = krealloc(block, (valid_extensions + 1) * EDID_LENGTH, GFP_KERNEL);
  		if (!new)
  			goto out;
  		block = new;
  	}
  
  	return block;
  
  carp:
  	dev_warn(connector->dev->dev, "%s: EDID block %d invalid.\n",
  		 drm_get_connector_name(connector), j);
  
  out:
  	kfree(block);
  	return NULL;
  }
  
  /**
   * Probe DDC presence.
   *
   * \param adapter : i2c device adaptor
   * \return 1 on success
   */
  static bool
  drm_probe_ddc(struct i2c_adapter *adapter)
  {
  	unsigned char out;
  
  	return (drm_do_probe_ddc_edid(adapter, &out, 0, 1) == 0);
  }
  
  /**
   * drm_get_edid - get EDID data, if available
   * @connector: connector we're probing
   * @adapter: i2c adapter to use for DDC
   *
   * Poke the given i2c channel to grab EDID data if possible.  If found,
   * attach it to the connector.
   *
   * 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 = NULL;
  
  	if (drm_probe_ddc(adapter))
  		edid = (struct edid *)drm_do_get_edid(connector, adapter);
  
  	connector->display_info.raw_edid = (char *)edid;
  
  	return edid;
  
  }
  EXPORT_SYMBOL(drm_get_edid);
  
  /*** EDID parsing ***/
  
  /**
   * 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[1] & 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 = 0;
  
  	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;
  }
  
  static bool
  mode_is_rb(const struct drm_display_mode *mode)
  {
  	return (mode->htotal - mode->hdisplay == 160) &&
  	       (mode->hsync_end - mode->hdisplay == 80) &&
  	       (mode->hsync_end - mode->hsync_start == 32) &&
  	       (mode->vsync_start - mode->vdisplay == 3);
  }
  
  /*
   * drm_mode_find_dmt - Create a copy of a mode if present in DMT
   * @dev: Device to duplicate against
   * @hsize: Mode width
   * @vsize: Mode height
   * @fresh: Mode refresh rate
   * @rb: Mode reduced-blanking-ness
   *
   * Walk the DMT mode list looking for a match for the given parameters.
   * Return a newly allocated copy of the mode, or NULL if not found.
   */
  struct drm_display_mode *drm_mode_find_dmt(struct drm_device *dev,
  					   int hsize, int vsize, int fresh,
  					   bool rb)
  {
  	int i;
  
  	for (i = 0; i < drm_num_dmt_modes; i++) {
  		const struct drm_display_mode *ptr = &drm_dmt_modes[i];
  		if (hsize != ptr->hdisplay)
  			continue;
  		if (vsize != ptr->vdisplay)
  			continue;
  		if (fresh != drm_mode_vrefresh(ptr))
  			continue;
  		if (rb != mode_is_rb(ptr))
  			continue;
  
  		return drm_mode_duplicate(dev, ptr);
  	}
  
  	return NULL;
  }
  EXPORT_SYMBOL(drm_mode_find_dmt);
  
  typedef void detailed_cb(struct detailed_timing *timing, void *closure);
  
  static void
  cea_for_each_detailed_block(u8 *ext, detailed_cb *cb, void *closure)
  {
  	int i, n = 0;
  	u8 d = ext[0x02];
  	u8 *det_base = ext + d;
  
  	n = (127 - d) / 18;
  	for (i = 0; i < n; i++)
  		cb((struct detailed_timing *)(det_base + 18 * i), closure);
  }
  
  static void
  vtb_for_each_detailed_block(u8 *ext, detailed_cb *cb, void *closure)
  {
  	unsigned int i, n = min((int)ext[0x02], 6);
  	u8 *det_base = ext + 5;
  
  	if (ext[0x01] != 1)
  		return; /* unknown version */
  
  	for (i = 0; i < n; i++)
  		cb((struct detailed_timing *)(det_base + 18 * i), closure);
  }
  
  static void
  drm_for_each_detailed_block(u8 *raw_edid, detailed_cb *cb, void *closure)
  {
  	int i;
  	struct edid *edid = (struct edid *)raw_edid;
  
  	if (edid == NULL)
  		return;
  
  	for (i = 0; i < EDID_DETAILED_TIMINGS; i++)
  		cb(&(edid->detailed_timings[i]), closure);
  
  	for (i = 1; i <= raw_edid[0x7e]; i++) {
  		u8 *ext = raw_edid + (i * EDID_LENGTH);
  		switch (*ext) {
  		case CEA_EXT:
  			cea_for_each_detailed_block(ext, cb, closure);
  			break;
  		case VTB_EXT:
  			vtb_for_each_detailed_block(ext, cb, closure);
  			break;
  		default:
  			break;
  		}
  	}
  }
  
  static void
  is_rb(struct detailed_timing *t, void *data)
  {
  	u8 *r = (u8 *)t;
  	if (r[3] == EDID_DETAIL_MONITOR_RANGE)
  		if (r[15] & 0x10)
  			*(bool *)data = true;
  }
  
  /* EDID 1.4 defines this explicitly.  For EDID 1.3, we guess, badly. */
  static bool
  drm_monitor_supports_rb(struct edid *edid)
  {
  	if (edid->revision >= 4) {
  		bool ret = false;
  		drm_for_each_detailed_block((u8 *)edid, is_rb, &ret);
  		return ret;
  	}
  
  	return ((edid->input & DRM_EDID_INPUT_DIGITAL) != 0);
  }
  
  static void
  find_gtf2(struct detailed_timing *t, void *data)
  {
  	u8 *r = (u8 *)t;
  	if (r[3] == EDID_DETAIL_MONITOR_RANGE && r[10] == 0x02)
  		*(u8 **)data = r;
  }
  
  /* Secondary GTF curve kicks in above some break frequency */
  static int
  drm_gtf2_hbreak(struct edid *edid)
  {
  	u8 *r = NULL;
  	drm_for_each_detailed_block((u8 *)edid, find_gtf2, &r);
  	return r ? (r[12] * 2) : 0;
  }
  
  static int
  drm_gtf2_2c(struct edid *edid)
  {
  	u8 *r = NULL;
  	drm_for_each_detailed_block((u8 *)edid, find_gtf2, &r);
  	return r ? r[13] : 0;
  }
  
  static int
  drm_gtf2_m(struct edid *edid)
  {
  	u8 *r = NULL;
  	drm_for_each_detailed_block((u8 *)edid, find_gtf2, &r);
  	return r ? (r[15] << 8) + r[14] : 0;
  }
  
  static int
  drm_gtf2_k(struct edid *edid)
  {
  	u8 *r = NULL;
  	drm_for_each_detailed_block((u8 *)edid, find_gtf2, &r);
  	return r ? r[16] : 0;
  }
  
  static int
  drm_gtf2_2j(struct edid *edid)
  {
  	u8 *r = NULL;
  	drm_for_each_detailed_block((u8 *)edid, find_gtf2, &r);
  	return r ? r[17] : 0;
  }
  
  /**
   * standard_timing_level - get std. timing level(CVT/GTF/DMT)
   * @edid: EDID block to scan
   */
  static int standard_timing_level(struct edid *edid)
  {
  	if (edid->revision >= 2) {
  		if (edid->revision >= 4 && (edid->features & DRM_EDID_FEATURE_DEFAULT_GTF))
  			return LEVEL_CVT;
  		if (drm_gtf2_hbreak(edid))
  			return LEVEL_GTF2;
  		return LEVEL_GTF;
  	}
  	return LEVEL_DMT;
  }
  
  /*
   * 0 is reserved.  The spec says 0x01 fill for unused timings.  Some old
   * monitors fill with ascii space (0x20) instead.
   */
  static int
  bad_std_timing(u8 a, u8 b)
  {
  	return (a == 0x00 && b == 0x00) ||
  	       (a == 0x01 && b == 0x01) ||
  	       (a == 0x20 && b == 0x20);
  }
  
  /**
   * drm_mode_std - convert standard mode info (width, height, refresh) into mode
   * @t: standard timing params
   * @timing_level: standard timing level
   *
   * Take the standard timing params (in this case width, aspect, and refresh)
   * and convert them into a real mode using CVT/GTF/DMT.
   */
  static struct drm_display_mode *
  drm_mode_std(struct drm_connector *connector, struct edid *edid,
  	     struct std_timing *t, int revision)
  {
  	struct drm_device *dev = connector->dev;
  	struct drm_display_mode *m, *mode = NULL;
  	int hsize, vsize;
  	int vrefresh_rate;
  	unsigned aspect_ratio = (t->vfreq_aspect & EDID_TIMING_ASPECT_MASK)
  		>> EDID_TIMING_ASPECT_SHIFT;
  	unsigned vfreq = (t->vfreq_aspect & EDID_TIMING_VFREQ_MASK)
  		>> EDID_TIMING_VFREQ_SHIFT;
  	int timing_level = standard_timing_level(edid);
  
  	if (bad_std_timing(t->hsize, t->vfreq_aspect))
  		return NULL;
  
  	/* According to the EDID spec, the hdisplay = hsize * 8 + 248 */
  	hsize = t->hsize * 8 + 248;
  	/* vrefresh_rate = vfreq + 60 */
  	vrefresh_rate = vfreq + 60;
  	/* the vdisplay is calculated based on the aspect ratio */
  	if (aspect_ratio == 0) {
  		if (revision < 3)
  			vsize = hsize;
  		else
  			vsize = (hsize * 10) / 16;
  	} else if (aspect_ratio == 1)
  		vsize = (hsize * 3) / 4;
  	else if (aspect_ratio == 2)
  		vsize = (hsize * 4) / 5;
  	else
  		vsize = (hsize * 9) / 16;
  
  	/* HDTV hack, part 1 */
  	if (vrefresh_rate == 60 &&
  	    ((hsize == 1360 && vsize == 765) ||
  	     (hsize == 1368 && vsize == 769))) {
  		hsize = 1366;
  		vsize = 768;
  	}
  
  	/*
  	 * If this connector already has a mode for this size and refresh
  	 * rate (because it came from detailed or CVT info), use that
  	 * instead.  This way we don't have to guess at interlace or
  	 * reduced blanking.
  	 */
  	list_for_each_entry(m, &connector->probed_modes, head)
  		if (m->hdisplay == hsize && m->vdisplay == vsize &&
  		    drm_mode_vrefresh(m) == vrefresh_rate)
  			return NULL;
  
  	/* HDTV hack, part 2 */
  	if (hsize == 1366 && vsize == 768 && vrefresh_rate == 60) {
  		mode = drm_cvt_mode(dev, 1366, 768, vrefresh_rate, 0, 0,
  				    false);
  		mode->hdisplay = 1366;
  		mode->hsync_start = mode->hsync_start - 1;
  		mode->hsync_end = mode->hsync_end - 1;
  		return mode;
  	}
  
  	/* check whether it can be found in default mode table */
  	if (drm_monitor_supports_rb(edid)) {
  		mode = drm_mode_find_dmt(dev, hsize, vsize, vrefresh_rate,
  					 true);
  		if (mode)
  			return mode;
  	}
  	mode = drm_mode_find_dmt(dev, hsize, vsize, vrefresh_rate, false);
  	if (mode)
  		return mode;
  
  	/* okay, generate it */
  	switch (timing_level) {
  	case LEVEL_DMT:
  		break;
  	case LEVEL_GTF:
  		mode = drm_gtf_mode(dev, hsize, vsize, vrefresh_rate, 0, 0);
  		break;
  	case LEVEL_GTF2:
  		/*
  		 * This is potentially wrong if there's ever a monitor with
  		 * more than one ranges section, each claiming a different
  		 * secondary GTF curve.  Please don't do that.
  		 */
  		mode = drm_gtf_mode(dev, hsize, vsize, vrefresh_rate, 0, 0);
  		if (!mode)
  			return NULL;
  		if (drm_mode_hsync(mode) > drm_gtf2_hbreak(edid)) {
  			drm_mode_destroy(dev, mode);
  			mode = drm_gtf_mode_complex(dev, hsize, vsize,
  						    vrefresh_rate, 0, 0,
  						    drm_gtf2_m(edid),
  						    drm_gtf2_2c(edid),
  						    drm_gtf2_k(edid),
  						    drm_gtf2_2j(edid));
  		}
  		break;
  	case LEVEL_CVT:
  		mode = drm_cvt_mode(dev, hsize, vsize, vrefresh_rate, 0, 0,
  				    false);
  		break;
  	}
  	return mode;
  }
  
  /*
   * EDID is delightfully ambiguous about how interlaced modes are to be
   * encoded.  Our internal representation is of frame height, but some
   * HDTV detailed timings are encoded as field height.
   *
   * The format list here is from CEA, in frame size.  Technically we
   * should be checking refresh rate too.  Whatever.
   */
  static void
  drm_mode_do_interlace_quirk(struct drm_display_mode *mode,
  			    struct detailed_pixel_timing *pt)
  {
  	int i;
  	static const struct {
  		int w, h;
  	} cea_interlaced[] = {
  		{ 1920, 1080 },
  		{  720,  480 },
  		{ 1440,  480 },
  		{ 2880,  480 },
  		{  720,  576 },
  		{ 1440,  576 },
  		{ 2880,  576 },
  	};
  
  	if (!(pt->misc & DRM_EDID_PT_INTERLACED))
  		return;
  
  	for (i = 0; i < ARRAY_SIZE(cea_interlaced); i++) {
  		if ((mode->hdisplay == cea_interlaced[i].w) &&
  		    (mode->vdisplay == cea_interlaced[i].h / 2)) {
  			mode->vdisplay *= 2;
  			mode->vsync_start *= 2;
  			mode->vsync_end *= 2;
  			mode->vtotal *= 2;
  			mode->vtotal |= 1;
  		}
  	}
  
  	mode->flags |= DRM_MODE_FLAG_INTERLACE;
  }
  
  /**
   * 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;
  	unsigned hactive = (pt->hactive_hblank_hi & 0xf0) << 4 | pt->hactive_lo;
  	unsigned vactive = (pt->vactive_vblank_hi & 0xf0) << 4 | pt->vactive_lo;
  	unsigned hblank = (pt->hactive_hblank_hi & 0xf) << 8 | pt->hblank_lo;
  	unsigned vblank = (pt->vactive_vblank_hi & 0xf) << 8 | pt->vblank_lo;
  	unsigned hsync_offset = (pt->hsync_vsync_offset_pulse_width_hi & 0xc0) << 2 | pt->hsync_offset_lo;
  	unsigned hsync_pulse_width = (pt->hsync_vsync_offset_pulse_width_hi & 0x30) << 4 | pt->hsync_pulse_width_lo;
  	unsigned vsync_offset = (pt->hsync_vsync_offset_pulse_width_hi & 0xc) >> 2 | pt->vsync_offset_pulse_width_lo >> 4;
  	unsigned vsync_pulse_width = (pt->hsync_vsync_offset_pulse_width_hi & 0x3) << 4 | (pt->vsync_offset_pulse_width_lo & 0xf);
  
  	/* ignore tiny modes */
  	if (hactive < 64 || vactive < 64)
  		return NULL;
  
  	if (pt->misc & DRM_EDID_PT_STEREO) {
  		printk(KERN_WARNING "stereo mode not supported\n");
  		return NULL;
  	}
  	if (!(pt->misc & DRM_EDID_PT_SEPARATE_SYNC)) {
  		printk(KERN_WARNING "composite sync not supported\n");
  	}
  
  	/* it is incorrect if hsync/vsync width is zero */
  	if (!hsync_pulse_width || !vsync_pulse_width) {
  		DRM_DEBUG_KMS("Incorrect Detailed timing. "
  				"Wrong Hsync/Vsync pulse width\n");
  		return NULL;
  	}
  
  	if (quirks & EDID_QUIRK_FORCE_REDUCED_BLANKING) {
  		mode = drm_cvt_mode(dev, hactive, vactive, 60, true, false, false);
  		if (!mode)
  			return NULL;
  
  		goto set_size;
  	}
  
  	mode = drm_mode_create(dev);
  	if (!mode)
  		return NULL;
  
  	if (quirks & EDID_QUIRK_135_CLOCK_TOO_HIGH)
  		timing->pixel_clock = cpu_to_le16(1088);
  
  	mode->clock = le16_to_cpu(timing->pixel_clock) * 10;
  
  	mode->hdisplay = hactive;
  	mode->hsync_start = mode->hdisplay + hsync_offset;
  	mode->hsync_end = mode->hsync_start + hsync_pulse_width;
  	mode->htotal = mode->hdisplay + hblank;
  
  	mode->vdisplay = vactive;
  	mode->vsync_start = mode->vdisplay + vsync_offset;
  	mode->vsync_end = mode->vsync_start + vsync_pulse_width;
  	mode->vtotal = mode->vdisplay + vblank;
  
  	/* Some EDIDs have bogus h/vtotal values */
  	if (mode->hsync_end > mode->htotal)
  		mode->htotal = mode->hsync_end + 1;
  	if (mode->vsync_end > mode->vtotal)
  		mode->vtotal = mode->vsync_end + 1;
  
  	drm_mode_do_interlace_quirk(mode, pt);
  
  	if (quirks & EDID_QUIRK_DETAILED_SYNC_PP) {
  		pt->misc |= DRM_EDID_PT_HSYNC_POSITIVE | DRM_EDID_PT_VSYNC_POSITIVE;
  	}
  
  	mode->flags |= (pt->misc & DRM_EDID_PT_HSYNC_POSITIVE) ?
  		DRM_MODE_FLAG_PHSYNC : DRM_MODE_FLAG_NHSYNC;
  	mode->flags |= (pt->misc & DRM_EDID_PT_VSYNC_POSITIVE) ?
  		DRM_MODE_FLAG_PVSYNC : DRM_MODE_FLAG_NVSYNC;
  
  set_size:
  	mode->width_mm = pt->width_mm_lo | (pt->width_height_mm_hi & 0xf0) << 4;
  	mode->height_mm = pt->height_mm_lo | (pt->width_height_mm_hi & 0xf) << 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;
  	}
  
  	mode->type = DRM_MODE_TYPE_DRIVER;
  	drm_mode_set_name(mode);
  
  	return mode;
  }
  
  static bool
  mode_in_hsync_range(const struct drm_display_mode *mode,
  		    struct edid *edid, u8 *t)
  {
  	int hsync, hmin, hmax;
  
  	hmin = t[7];
  	if (edid->revision >= 4)
  	    hmin += ((t[4] & 0x04) ? 255 : 0);
  	hmax = t[8];
  	if (edid->revision >= 4)
  	    hmax += ((t[4] & 0x08) ? 255 : 0);
  	hsync = drm_mode_hsync(mode);
  
  	return (hsync <= hmax && hsync >= hmin);
  }
  
  static bool
  mode_in_vsync_range(const struct drm_display_mode *mode,
  		    struct edid *edid, u8 *t)
  {
  	int vsync, vmin, vmax;
  
  	vmin = t[5];
  	if (edid->revision >= 4)
  	    vmin += ((t[4] & 0x01) ? 255 : 0);
  	vmax = t[6];
  	if (edid->revision >= 4)
  	    vmax += ((t[4] & 0x02) ? 255 : 0);
  	vsync = drm_mode_vrefresh(mode);
  
  	return (vsync <= vmax && vsync >= vmin);
  }
  
  static u32
  range_pixel_clock(struct edid *edid, u8 *t)
  {
  	/* unspecified */
  	if (t[9] == 0 || t[9] == 255)
  		return 0;
  
  	/* 1.4 with CVT support gives us real precision, yay */
  	if (edid->revision >= 4 && t[10] == 0x04)
  		return (t[9] * 10000) - ((t[12] >> 2) * 250);
  
  	/* 1.3 is pathetic, so fuzz up a bit */
  	return t[9] * 10000 + 5001;
  }
  
  static bool
  mode_in_range(const struct drm_display_mode *mode, struct edid *edid,
  	      struct detailed_timing *timing)
  {
  	u32 max_clock;
  	u8 *t = (u8 *)timing;
  
  	if (!mode_in_hsync_range(mode, edid, t))
  		return false;
  
  	if (!mode_in_vsync_range(mode, edid, t))
  		return false;
  
  	if ((max_clock = range_pixel_clock(edid, t)))
  		if (mode->clock > max_clock)
  			return false;
  
  	/* 1.4 max horizontal check */
  	if (edid->revision >= 4 && t[10] == 0x04)
  		if (t[13] && mode->hdisplay > 8 * (t[13] + (256 * (t[12]&0x3))))
  			return false;
  
  	if (mode_is_rb(mode) && !drm_monitor_supports_rb(edid))
  		return false;
  
  	return true;
  }
  
  static bool valid_inferred_mode(const struct drm_connector *connector,
  				const struct drm_display_mode *mode)
  {
  	struct drm_display_mode *m;
  	bool ok = false;
  
  	list_for_each_entry(m, &connector->probed_modes, head) {
  		if (mode->hdisplay == m->hdisplay &&
  		    mode->vdisplay == m->vdisplay &&
  		    drm_mode_vrefresh(mode) == drm_mode_vrefresh(m))
  			return false; /* duplicated */
  		if (mode->hdisplay <= m->hdisplay &&
  		    mode->vdisplay <= m->vdisplay)
  			ok = true;
  	}
  	return ok;
  }
  
  static int
  drm_dmt_modes_for_range(struct drm_connector *connector, struct edid *edid,
  			struct detailed_timing *timing)
  {
  	int i, modes = 0;
  	struct drm_display_mode *newmode;
  	struct drm_device *dev = connector->dev;
  
  	for (i = 0; i < drm_num_dmt_modes; i++) {
  		if (mode_in_range(drm_dmt_modes + i, edid, timing) &&
  		    valid_inferred_mode(connector, drm_dmt_modes + i)) {
  			newmode = drm_mode_duplicate(dev, &drm_dmt_modes[i]);
  			if (newmode) {
  				drm_mode_probed_add(connector, newmode);
  				modes++;
  			}
  		}
  	}
  
  	return modes;
  }
  
  /* fix up 1366x768 mode from 1368x768;
   * GFT/CVT can't express 1366 width which isn't dividable by 8
   */
  static void fixup_mode_1366x768(struct drm_display_mode *mode)
  {
  	if (mode->hdisplay == 1368 && mode->vdisplay == 768) {
  		mode->hdisplay = 1366;
  		mode->hsync_start--;
  		mode->hsync_end--;
  		drm_mode_set_name(mode);
  	}
  }
  
  static int
  drm_gtf_modes_for_range(struct drm_connector *connector, struct edid *edid,
  			struct detailed_timing *timing)
  {
  	int i, modes = 0;
  	struct drm_display_mode *newmode;
  	struct drm_device *dev = connector->dev;
  
  	for (i = 0; i < num_extra_modes; i++) {
  		const struct minimode *m = &extra_modes[i];
  		newmode = drm_gtf_mode(dev, m->w, m->h, m->r, 0, 0);
  		if (!newmode)
  			return modes;
  
  		fixup_mode_1366x768(newmode);
  		if (!mode_in_range(newmode, edid, timing) ||
  		    !valid_inferred_mode(connector, newmode)) {
  			drm_mode_destroy(dev, newmode);
  			continue;
  		}
  
  		drm_mode_probed_add(connector, newmode);
  		modes++;
  	}
  
  	return modes;
  }
  
  static int
  drm_cvt_modes_for_range(struct drm_connector *connector, struct edid *edid,
  			struct detailed_timing *timing)
  {
  	int i, modes = 0;
  	struct drm_display_mode *newmode;
  	struct drm_device *dev = connector->dev;
  	bool rb = drm_monitor_supports_rb(edid);
  
  	for (i = 0; i < num_extra_modes; i++) {
  		const struct minimode *m = &extra_modes[i];
  		newmode = drm_cvt_mode(dev, m->w, m->h, m->r, rb, 0, 0);
  		if (!newmode)
  			return modes;
  
  		fixup_mode_1366x768(newmode);
  		if (!mode_in_range(newmode, edid, timing) ||
  		    !valid_inferred_mode(connector, newmode)) {
  			drm_mode_destroy(dev, newmode);
  			continue;
  		}
  
  		drm_mode_probed_add(connector, newmode);
  		modes++;
  	}
  
  	return modes;
  }
  
  static void
  do_inferred_modes(struct detailed_timing *timing, void *c)
  {
  	struct detailed_mode_closure *closure = c;
  	struct detailed_non_pixel *data = &timing->data.other_data;
  	struct detailed_data_monitor_range *range = &data->data.range;
  
  	if (data->type != EDID_DETAIL_MONITOR_RANGE)
  		return;
  
  	closure->modes += drm_dmt_modes_for_range(closure->connector,
  						  closure->edid,
  						  timing);
  	
  	if (!version_greater(closure->edid, 1, 1))
  		return; /* GTF not defined yet */
  
  	switch (range->flags) {
  	case 0x02: /* secondary gtf, XXX could do more */
  	case 0x00: /* default gtf */
  		closure->modes += drm_gtf_modes_for_range(closure->connector,
  							  closure->edid,
  							  timing);
  		break;
  	case 0x04: /* cvt, only in 1.4+ */
  		if (!version_greater(closure->edid, 1, 3))
  			break;
  
  		closure->modes += drm_cvt_modes_for_range(closure->connector,
  							  closure->edid,
  							  timing);
  		break;
  	case 0x01: /* just the ranges, no formula */
  	default:
  		break;
  	}
  }
  
  static int
  add_inferred_modes(struct drm_connector *connector, struct edid *edid)
  {
  	struct detailed_mode_closure closure = {
  		connector, edid, 0, 0, 0
  	};
  
  	if (version_greater(edid, 1, 0))
  		drm_for_each_detailed_block((u8 *)edid, do_inferred_modes,
  					    &closure);
  
  	return closure.modes;
  }
  
  static int
  drm_est3_modes(struct drm_connector *connector, struct detailed_timing *timing)
  {
  	int i, j, m, modes = 0;
  	struct drm_display_mode *mode;
  	u8 *est = ((u8 *)timing) + 5;
  
  	for (i = 0; i < 6; i++) {
  		for (j = 7; j > 0; j--) {
  			m = (i * 8) + (7 - j);
  			if (m >= ARRAY_SIZE(est3_modes))
  				break;
  			if (est[i] & (1 << j)) {
  				mode = drm_mode_find_dmt(connector->dev,
  							 est3_modes[m].w,
  							 est3_modes[m].h,
  							 est3_modes[m].r,
  							 est3_modes[m].rb);
  				if (mode) {
  					drm_mode_probed_add(connector, mode);
  					modes++;
  				}
  			}
  		}
  	}
  
  	return modes;
  }
  
  static void
  do_established_modes(struct detailed_timing *timing, void *c)
  {
  	struct detailed_mode_closure *closure = c;
  	struct detailed_non_pixel *data = &timing->data.other_data;
  
  	if (data->type == EDID_DETAIL_EST_TIMINGS)
  		closure->modes += drm_est3_modes(closure->connector, timing);
  }
  
  /**
   * 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;
  	struct detailed_mode_closure closure = {
  		connector, edid, 0, 0, 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++;
  			}
  		}
  	}
  
  	if (version_greater(edid, 1, 0))
  		    drm_for_each_detailed_block((u8 *)edid,
  						do_established_modes, &closure);
  
  	return modes + closure.modes;
  }
  
  static void
  do_standard_modes(struct detailed_timing *timing, void *c)
  {
  	struct detailed_mode_closure *closure = c;
  	struct detailed_non_pixel *data = &timing->data.other_data;
  	struct drm_connector *connector = closure->connector;
  	struct edid *edid = closure->edid;
  
  	if (data->type == EDID_DETAIL_STD_MODES) {
  		int i;
  		for (i = 0; i < 6; i++) {
  			struct std_timing *std;
  			struct drm_display_mode *newmode;
  
  			std = &data->data.timings[i];
  			newmode = drm_mode_std(connector, edid, std,
  					       edid->revision);
  			if (newmode) {
  				drm_mode_probed_add(connector, newmode);
  				closure->modes++;
  			}
  		}
  	}
  }
  
  /**
   * add_standard_modes - get std. modes from EDID and add them
   * @edid: EDID block to scan
   *
   * Standard modes can be calculated using the appropriate standard (DMT,
   * GTF or CVT. Grab them from @edid and add them to the list.
   */
  static int
  add_standard_modes(struct drm_connector *connector, struct edid *edid)
  {
  	int i, modes = 0;
  	struct detailed_mode_closure closure = {
  		connector, edid, 0, 0, 0
  	};
  
  	for (i = 0; i < EDID_STD_TIMINGS; i++) {
  		struct drm_display_mode *newmode;
  
  		newmode = drm_mode_std(connector, edid,
  				       &edid->standard_timings[i],
  				       edid->revision);
  		if (newmode) {
  			drm_mode_probed_add(connector, newmode);
  			modes++;
  		}
  	}
  
  	if (version_greater(edid, 1, 0))
  		drm_for_each_detailed_block((u8 *)edid, do_standard_modes,
  					    &closure);
  
  	/* XXX should also look for standard codes in VTB blocks */
  
  	return modes + closure.modes;
  }
  
  static int drm_cvt_modes(struct drm_connector *connector,
  			 struct detailed_timing *timing)
  {
  	int i, j, modes = 0;
  	struct drm_display_mode *newmode;
  	struct drm_device *dev = connector->dev;
  	struct cvt_timing *cvt;
  	const int rates[] = { 60, 85, 75, 60, 50 };
  	const u8 empty[3] = { 0, 0, 0 };
  
  	for (i = 0; i < 4; i++) {
  		int uninitialized_var(width), height;
  		cvt = &(timing->data.other_data.data.cvt[i]);
  
  		if (!memcmp(cvt->code, empty, 3))
  			continue;
  
  		height = (cvt->code[0] + ((cvt->code[1] & 0xf0) << 4) + 1) * 2;
  		switch (cvt->code[1] & 0x0c) {
  		case 0x00:
  			width = height * 4 / 3;
  			break;
  		case 0x04:
  			width = height * 16 / 9;
  			break;
  		case 0x08:
  			width = height * 16 / 10;
  			break;
  		case 0x0c:
  			width = height * 15 / 9;
  			break;
  		}
  
  		for (j = 1; j < 5; j++) {
  			if (cvt->code[2] & (1 << j)) {
  				newmode = drm_cvt_mode(dev, width, height,
  						       rates[j], j == 0,
  						       false, false);
  				if (newmode) {
  					drm_mode_probed_add(connector, newmode);
  					modes++;
  				}
  			}
  		}
  	}
  
  	return modes;
  }
  
  static void
  do_cvt_mode(struct detailed_timing *timing, void *c)
  {
  	struct detailed_mode_closure *closure = c;
  	struct detailed_non_pixel *data = &timing->data.other_data;
  
  	if (data->type == EDID_DETAIL_CVT_3BYTE)
  		closure->modes += drm_cvt_modes(closure->connector, timing);
  }
  
  static int
  add_cvt_modes(struct drm_connector *connector, struct edid *edid)
  {	
  	struct detailed_mode_closure closure = {
  		connector, edid, 0, 0, 0
  	};
  
  	if (version_greater(edid, 1, 2))
  		drm_for_each_detailed_block((u8 *)edid, do_cvt_mode, &closure);
  
  	/* XXX should also look for CVT codes in VTB blocks */
  
  	return closure.modes;
  }
  
  static void
  do_detailed_mode(struct detailed_timing *timing, void *c)
  {
  	struct detailed_mode_closure *closure = c;
  	struct drm_display_mode *newmode;
  
  	if (timing->pixel_clock) {
  		newmode = drm_mode_detailed(closure->connector->dev,
  					    closure->edid, timing,
  					    closure->quirks);
  		if (!newmode)
  			return;
  
  		if (closure->preferred)
  			newmode->type |= DRM_MODE_TYPE_PREFERRED;
  
  		drm_mode_probed_add(closure->connector, newmode);
  		closure->modes++;
  		closure->preferred = 0;
  	}
  }
  
  /*
   * add_detailed_modes - Add modes from detailed timings
   * @connector: attached connector
   * @edid: EDID block to scan
   * @quirks: quirks to apply
   */
  static int
  add_detailed_modes(struct drm_connector *connector, struct edid *edid,
  		   u32 quirks)
  {
  	struct detailed_mode_closure closure = {
  		connector,
  		edid,
  		1,
  		quirks,
  		0
  	};
  
  	if (closure.preferred && !version_greater(edid, 1, 3))
  		closure.preferred =
  		    (edid->features & DRM_EDID_FEATURE_PREFERRED_TIMING);
  
  	drm_for_each_detailed_block((u8 *)edid, do_detailed_mode, &closure);
  
  	return closure.modes;
  }
  
  #define HDMI_IDENTIFIER 0x000C03
  #define AUDIO_BLOCK	0x01
  #define VIDEO_BLOCK     0x02
  #define VENDOR_BLOCK    0x03
  #define SPEAKER_BLOCK	0x04
  #define EDID_BASIC_AUDIO	(1 << 6)
  #define EDID_CEA_YCRCB444	(1 << 5)
  #define EDID_CEA_YCRCB422	(1 << 4)
  
  /**
   * Search EDID for CEA extension block.
   */
  u8 *drm_find_cea_extension(struct edid *edid)
  {
  	u8 *edid_ext = NULL;
  	int i;
  
  	/* No EDID or EDID extensions */
  	if (edid == NULL || edid->extensions == 0)
  		return NULL;
  
  	/* Find CEA extension */
  	for (i = 0; i < edid->extensions; i++) {
  		edid_ext = (u8 *)edid + EDID_LENGTH * (i + 1);
  		if (edid_ext[0] == CEA_EXT)
  			break;
  	}
  
  	if (i == edid->extensions)
  		return NULL;
  
  	return edid_ext;
  }
  EXPORT_SYMBOL(drm_find_cea_extension);
  
  static int
  do_cea_modes (struct drm_connector *connector, u8 *db, u8 len)
  {
  	struct drm_device *dev = connector->dev;
  	u8 * mode, cea_mode;
  	int modes = 0;
  
  	for (mode = db; mode < db + len; mode++) {
  		cea_mode = (*mode & 127) - 1; /* CEA modes are numbered 1..127 */
  		if (cea_mode < drm_num_cea_modes) {
  			struct drm_display_mode *newmode;
  			newmode = drm_mode_duplicate(dev,
  						     &edid_cea_modes[cea_mode]);
  			if (newmode) {
  				drm_mode_probed_add(connector, newmode);
  				modes++;
  			}
  		}
  	}
  
  	return modes;
  }
  
  static int
  add_cea_modes(struct drm_connector *connector, struct edid *edid)
  {
  	u8 * cea = drm_find_cea_extension(edid);
  	u8 * db, dbl;
  	int modes = 0;
  
  	if (cea && cea[1] >= 3) {
  		for (db = cea + 4; db < cea + cea[2]; db += dbl + 1) {
  			dbl = db[0] & 0x1f;
  			if (((db[0] & 0xe0) >> 5) == VIDEO_BLOCK)
  				modes += do_cea_modes (connector, db+1, dbl);
  		}
  	}
  
  	return modes;
  }
  
  static void
  parse_hdmi_vsdb(struct drm_connector *connector, uint8_t *db)
  {
  	connector->eld[5] |= (db[6] >> 7) << 1;  /* Supports_AI */
  
  	connector->dvi_dual = db[6] & 1;
  	connector->max_tmds_clock = db[7] * 5;
  
  	connector->latency_present[0] = db[8] >> 7;
  	connector->latency_present[1] = (db[8] >> 6) & 1;
  	connector->video_latency[0] = db[9];
  	connector->audio_latency[0] = db[10];
  	connector->video_latency[1] = db[11];
  	connector->audio_latency[1] = db[12];
  
  	DRM_LOG_KMS("HDMI: DVI dual %d, "
  		    "max TMDS clock %d, "
  		    "latency present %d %d, "
  		    "video latency %d %d, "
  		    "audio latency %d %d\n",
  		    connector->dvi_dual,
  		    connector->max_tmds_clock,
  	      (int) connector->latency_present[0],
  	      (int) connector->latency_present[1],
  		    connector->video_latency[0],
  		    connector->video_latency[1],
  		    connector->audio_latency[0],
  		    connector->audio_latency[1]);
  }
  
  static void
  monitor_name(struct detailed_timing *t, void *data)
  {
  	if (t->data.other_data.type == EDID_DETAIL_MONITOR_NAME)
  		*(u8 **)data = t->data.other_data.data.str.str;
  }
  
  /**
   * drm_edid_to_eld - build ELD from EDID
   * @connector: connector corresponding to the HDMI/DP sink
   * @edid: EDID to parse
   *
   * Fill the ELD (EDID-Like Data) buffer for passing to the audio driver.
   * Some ELD fields are left to the graphics driver caller:
   * - Conn_Type
   * - HDCP
   * - Port_ID
   */
  void drm_edid_to_eld(struct drm_connector *connector, struct edid *edid)
  {
  	uint8_t *eld = connector->eld;
  	u8 *cea;
  	u8 *name;
  	u8 *db;
  	int sad_count = 0;
  	int mnl;
  	int dbl;
  
  	memset(eld, 0, sizeof(connector->eld));
  
  	cea = drm_find_cea_extension(edid);
  	if (!cea) {
  		DRM_DEBUG_KMS("ELD: no CEA Extension found\n");
  		return;
  	}
  
  	name = NULL;
  	drm_for_each_detailed_block((u8 *)edid, monitor_name, &name);
  	for (mnl = 0; name && mnl < 13; mnl++) {
  		if (name[mnl] == 0x0a)
  			break;
  		eld[20 + mnl] = name[mnl];
  	}
  	eld[4] = (cea[1] << 5) | mnl;
  	DRM_DEBUG_KMS("ELD monitor %s\n", eld + 20);
  
  	eld[0] = 2 << 3;		/* ELD version: 2 */
  
  	eld[16] = edid->mfg_id[0];
  	eld[17] = edid->mfg_id[1];
  	eld[18] = edid->prod_code[0];
  	eld[19] = edid->prod_code[1];
  
  	if (cea[1] >= 3)
  		for (db = cea + 4; db < cea + cea[2]; db += dbl + 1) {
  			dbl = db[0] & 0x1f;
  			
  			switch ((db[0] & 0xe0) >> 5) {
  			case AUDIO_BLOCK:
  				/* Audio Data Block, contains SADs */
  				sad_count = dbl / 3;
  				memcpy(eld + 20 + mnl, &db[1], dbl);
  				break;
  			case SPEAKER_BLOCK:
                                  /* Speaker Allocation Data Block */
  				eld[7] = db[1];
  				break;
  			case VENDOR_BLOCK:
  				/* HDMI Vendor-Specific Data Block */
  				if (db[1] == 0x03 && db[2] == 0x0c && db[3] == 0)
  					parse_hdmi_vsdb(connector, db);
  				break;
  			default:
  				break;
  			}
  		}
  	eld[5] |= sad_count << 4;
  	eld[2] = (20 + mnl + sad_count * 3 + 3) / 4;
  
  	DRM_DEBUG_KMS("ELD size %d, SAD count %d\n", (int)eld[2], sad_count);
  }
  EXPORT_SYMBOL(drm_edid_to_eld);
  
  /**
   * drm_av_sync_delay - HDMI/DP sink audio-video sync delay in millisecond
   * @connector: connector associated with the HDMI/DP sink
   * @mode: the display mode
   */
  int drm_av_sync_delay(struct drm_connector *connector,
  		      struct drm_display_mode *mode)
  {
  	int i = !!(mode->flags & DRM_MODE_FLAG_INTERLACE);
  	int a, v;
  
  	if (!connector->latency_present[0])
  		return 0;
  	if (!connector->latency_present[1])
  		i = 0;
  
  	a = connector->audio_latency[i];
  	v = connector->video_latency[i];
  
  	/*
  	 * HDMI/DP sink doesn't support audio or video?
  	 */
  	if (a == 255 || v == 255)
  		return 0;
  
  	/*
  	 * Convert raw EDID values to millisecond.
  	 * Treat unknown latency as 0ms.
  	 */
  	if (a)
  		a = min(2 * (a - 1), 500);
  	if (v)
  		v = min(2 * (v - 1), 500);
  
  	return max(v - a, 0);
  }
  EXPORT_SYMBOL(drm_av_sync_delay);
  
  /**
   * drm_select_eld - select one ELD from multiple HDMI/DP sinks
   * @encoder: the encoder just changed display mode
   * @mode: the adjusted display mode
   *
   * It's possible for one encoder to be associated with multiple HDMI/DP sinks.
   * The policy is now hard coded to simply use the first HDMI/DP sink's ELD.
   */
  struct drm_connector *drm_select_eld(struct drm_encoder *encoder,
  				     struct drm_display_mode *mode)
  {
  	struct drm_connector *connector;
  	struct drm_device *dev = encoder->dev;
  
  	list_for_each_entry(connector, &dev->mode_config.connector_list, head)
  		if (connector->encoder == encoder && connector->eld[0])
  			return connector;
  
  	return NULL;
  }
  EXPORT_SYMBOL(drm_select_eld);
  
  /**
   * drm_detect_hdmi_monitor - detect whether monitor is hdmi.
   * @edid: monitor EDID information
   *
   * Parse the CEA extension according to CEA-861-B.
   * Return true if HDMI, false if not or unknown.
   */
  bool drm_detect_hdmi_monitor(struct edid *edid)
  {
  	u8 *edid_ext;
  	int i, hdmi_id;
  	int start_offset, end_offset;
  	bool is_hdmi = false;
  
  	edid_ext = drm_find_cea_extension(edid);
  	if (!edid_ext)
  		goto end;
  
  	/* Data block offset in CEA extension block */
  	start_offset = 4;
  	end_offset = edid_ext[2];
  
  	/*
  	 * Because HDMI identifier is in Vendor Specific Block,
  	 * search it from all data blocks of CEA extension.
  	 */
  	for (i = start_offset; i < end_offset;
  		/* Increased by data block len */
  		i += ((edid_ext[i] & 0x1f) + 1)) {
  		/* Find vendor specific block */
  		if ((edid_ext[i] >> 5) == VENDOR_BLOCK) {
  			hdmi_id = edid_ext[i + 1] | (edid_ext[i + 2] << 8) |
  				  edid_ext[i + 3] << 16;
  			/* Find HDMI identifier */
  			if (hdmi_id == HDMI_IDENTIFIER)
  				is_hdmi = true;
  			break;
  		}
  	}
  
  end:
  	return is_hdmi;
  }
  EXPORT_SYMBOL(drm_detect_hdmi_monitor);
  
  /**
   * drm_detect_monitor_audio - check monitor audio capability
   *
   * Monitor should have CEA extension block.
   * If monitor has 'basic audio', but no CEA audio blocks, it's 'basic
   * audio' only. If there is any audio extension block and supported
   * audio format, assume at least 'basic audio' support, even if 'basic
   * audio' is not defined in EDID.
   *
   */
  bool drm_detect_monitor_audio(struct edid *edid)
  {
  	u8 *edid_ext;
  	int i, j;
  	bool has_audio = false;
  	int start_offset, end_offset;
  
  	edid_ext = drm_find_cea_extension(edid);
  	if (!edid_ext)
  		goto end;
  
  	has_audio = ((edid_ext[3] & EDID_BASIC_AUDIO) != 0);
  
  	if (has_audio) {
  		DRM_DEBUG_KMS("Monitor has basic audio support\n");
  		goto end;
  	}
  
  	/* Data block offset in CEA extension block */
  	start_offset = 4;
  	end_offset = edid_ext[2];
  
  	for (i = start_offset; i < end_offset;
  			i += ((edid_ext[i] & 0x1f) + 1)) {
  		if ((edid_ext[i] >> 5) == AUDIO_BLOCK) {
  			has_audio = true;
  			for (j = 1; j < (edid_ext[i] & 0x1f); j += 3)
  				DRM_DEBUG_KMS("CEA audio format %d\n",
  					      (edid_ext[i + j] >> 3) & 0xf);
  			goto end;
  		}
  	}
  end:
  	return has_audio;
  }
  EXPORT_SYMBOL(drm_detect_monitor_audio);
  
  /**
   * drm_add_display_info - pull display info out if present
   * @edid: EDID data
   * @info: display info (attached to connector)
   *
   * Grab any available display info and stuff it into the drm_display_info
   * structure that's part of the connector.  Useful for tracking bpp and
   * color spaces.
   */
  static void drm_add_display_info(struct edid *edid,
  				 struct drm_display_info *info)
  {
  	u8 *edid_ext;
  
  	info->width_mm = edid->width_cm * 10;
  	info->height_mm = edid->height_cm * 10;
  
  	/* driver figures it out in this case */
  	info->bpc = 0;
  	info->color_formats = 0;
  
  	if (edid->revision < 3)
  		return;
  
  	if (!(edid->input & DRM_EDID_INPUT_DIGITAL))
  		return;
  
  	/* Get data from CEA blocks if present */
  	edid_ext = drm_find_cea_extension(edid);
  	if (edid_ext) {
  		info->cea_rev = edid_ext[1];
  
  		/* The existence of a CEA block should imply RGB support */
  		info->color_formats = DRM_COLOR_FORMAT_RGB444;
  		if (edid_ext[3] & EDID_CEA_YCRCB444)
  			info->color_formats |= DRM_COLOR_FORMAT_YCRCB444;
  		if (edid_ext[3] & EDID_CEA_YCRCB422)
  			info->color_formats |= DRM_COLOR_FORMAT_YCRCB422;
  	}
  
  	/* Only defined for 1.4 with digital displays */
  	if (edid->revision < 4)
  		return;
  
  	switch (edid->input & DRM_EDID_DIGITAL_DEPTH_MASK) {
  	case DRM_EDID_DIGITAL_DEPTH_6:
  		info->bpc = 6;
  		break;
  	case DRM_EDID_DIGITAL_DEPTH_8:
  		info->bpc = 8;
  		break;
  	case DRM_EDID_DIGITAL_DEPTH_10:
  		info->bpc = 10;
  		break;
  	case DRM_EDID_DIGITAL_DEPTH_12:
  		info->bpc = 12;
  		break;
  	case DRM_EDID_DIGITAL_DEPTH_14:
  		info->bpc = 14;
  		break;
  	case DRM_EDID_DIGITAL_DEPTH_16:
  		info->bpc = 16;
  		break;
  	case DRM_EDID_DIGITAL_DEPTH_UNDEF:
  	default:
  		info->bpc = 0;
  		break;
  	}
  
  	info->color_formats |= DRM_COLOR_FORMAT_RGB444;
  	if (edid->features & DRM_EDID_FEATURE_RGB_YCRCB444)
  		info->color_formats |= DRM_COLOR_FORMAT_YCRCB444;
  	if (edid->features & DRM_EDID_FEATURE_RGB_YCRCB422)
  		info->color_formats |= DRM_COLOR_FORMAT_YCRCB422;
  }
  
  /**
   * 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 (!drm_edid_is_valid(edid)) {
  		dev_warn(connector->dev->dev, "%s: EDID invalid.\n",
  			 drm_get_connector_name(connector));
  		return 0;
  	}
  
  	quirks = edid_get_quirks(edid);
  
  	/*
  	 * EDID spec says modes should be preferred in this order:
  	 * - preferred detailed mode
  	 * - other detailed modes from base block
  	 * - detailed modes from extension blocks
  	 * - CVT 3-byte code modes
  	 * - standard timing codes
  	 * - established timing codes
  	 * - modes inferred from GTF or CVT range information
  	 *
  	 * We get this pretty much right.
  	 *
  	 * XXX order for additional mode types in extension blocks?
  	 */
  	num_modes += add_detailed_modes(connector, edid, quirks);
  	num_modes += add_cvt_modes(connector, edid);
  	num_modes += add_standard_modes(connector, edid);
  	num_modes += add_established_modes(connector, edid);
  	num_modes += add_inferred_modes(connector, edid);
  	num_modes += add_cea_modes(connector, edid);
  
  	if (quirks & (EDID_QUIRK_PREFER_LARGE_60 | EDID_QUIRK_PREFER_LARGE_75))
  		edid_fixup_preferred(connector, quirks);
  
  	drm_add_display_info(edid, &connector->display_info);
  
  	return num_modes;
  }
  EXPORT_SYMBOL(drm_add_edid_modes);
  
  /**
   * drm_add_modes_noedid - add modes for the connectors without EDID
   * @connector: connector we're probing
   * @hdisplay: the horizontal display limit
   * @vdisplay: the vertical display limit
   *
   * Add the specified modes to the connector's mode list. Only when the
   * hdisplay/vdisplay is not beyond the given limit, it will be added.
   *
   * Return number of modes added or 0 if we couldn't find any.
   */
  int drm_add_modes_noedid(struct drm_connector *connector,
  			int hdisplay, int vdisplay)
  {
  	int i, count, num_modes = 0;
  	struct drm_display_mode *mode;
  	struct drm_device *dev = connector->dev;
  
  	count = sizeof(drm_dmt_modes) / sizeof(struct drm_display_mode);
  	if (hdisplay < 0)
  		hdisplay = 0;
  	if (vdisplay < 0)
  		vdisplay = 0;
  
  	for (i = 0; i < count; i++) {
  		const struct drm_display_mode *ptr = &drm_dmt_modes[i];
  		if (hdisplay && vdisplay) {
  			/*
  			 * Only when two are valid, they will be used to check
  			 * whether the mode should be added to the mode list of
  			 * the connector.
  			 */
  			if (ptr->hdisplay > hdisplay ||
  					ptr->vdisplay > vdisplay)
  				continue;
  		}
  		if (drm_mode_vrefresh(ptr) > 61)
  			continue;
  		mode = drm_mode_duplicate(dev, ptr);
  		if (mode) {
  			drm_mode_probed_add(connector, mode);
  			num_modes++;
  		}
  	}
  	return num_modes;
  }
  EXPORT_SYMBOL(drm_add_modes_noedid);
  