path: root/drivers/gpu/drm/drm_edid.c

/*
 * 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 "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)

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;
	int product_id;
	u32 quirks;
} edid_quirk_list[] = {
	/* Acer AL1706 */
	{ "ACR", 44358, EDID_QUIRK_PREFER_LARGE_60 },
	/* Acer F51 */
	{ "API", 0x7602, EDID_QUIRK_PREFER_LARGE_60 },
	/* Unknown Acer */
	{ "ACR", 2423, EDID_QUIRK_FIRST_DETAILED_PREFERRED },

	/* Belinea 10 15 55 */
	{ "MAX", 1516, EDID_QUIRK_PREFER_LARGE_60 },
	{ "MAX", 0x77e, EDID_QUIRK_PREFER_LARGE_60 },

	/* Envision Peripherals, Inc. EN-7100e */
	{ "EPI", 59264, EDID_QUIRK_135_CLOCK_TOO_HIGH },
	/* 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 },
};

/*** 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);


/*
 * Sanity check the EDID block (base or extension).  Return 0 if the block
 * doesn't check out, or 1 if it's valid.
 */
static bool
drm_edid_block_valid(u8 *raw_edid)
{
	int i;
	u8 csum = 0;
	struct edid *edid = (struct edid *)raw_edid;

	if (raw_edid[0] == 0x00) {
		int score = drm_edid_header_is_valid(raw_edid);
		if (score == 8) ;
		else if (score >= 6) {
			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 +=