1. 根目录:
2. drivers
3. gpu
4. drm
5. drm_edid_load.c

/*
   drm_edid_load.c: use a built-in EDID data set or load it via the firmware
		    interface

   Copyright (C) 2012 Carsten Emde <C.Emde@osadl.org>

   This program is free software; you can redistribute it and/or
   modify it under the terms of the GNU General Public License
   as published by the Free Software Foundation; either version 2
   of the License, or (at your option) any later version.

   This program is distributed in the hope that it will be useful,
   but WITHOUT ANY WARRANTY; without even the implied warranty of
   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
   GNU General Public License for more details.

   You should have received a copy of the GNU General Public License
   along with this program; if not, write to the Free Software
   Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA.
*/

#include <linux/module.h>
#include <linux/firmware.h>
#include <drm/drmP.h>
#include <drm/drm_crtc.h>
#include <drm/drm_crtc_helper.h>
#include <drm/drm_edid.h>

static char edid_firmware[PATH_MAX];
module_param_string(edid_firmware, edid_firmware, sizeof(edid_firmware), 0644);
MODULE_PARM_DESC(edid_firmware, "Do not probe monitor, use specified EDID blob "
	"from built-in data or /lib/firmware instead. ");

#define GENERIC_EDIDS 5
static char *generic_edid_name[GENERIC_EDIDS] = {
	"edid/1024x768.bin",
	"edid/1280x1024.bin",
	"edid/1600x1200.bin",
	"edid/1680x1050.bin",
	"edid/1920x1080.bin",
};

static u8 generic_edid[GENERIC_EDIDS][128] = {
	{
	0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00,
	0x31, 0xd8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x05, 0x16, 0x01, 0x03, 0x6d, 0x23, 0x1a, 0x78,
	0xea, 0x5e, 0xc0, 0xa4, 0x59, 0x4a, 0x98, 0x25,
	0x20, 0x50, 0x54, 0x00, 0x08, 0x00, 0x61, 0x40,
	0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
	0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x64, 0x19,
	0x00, 0x40, 0x41, 0x00, 0x26, 0x30, 0x08, 0x90,
	0x36, 0x00, 0x63, 0x0a, 0x11, 0x00, 0x00, 0x18,
	0x00, 0x00, 0x00, 0xff, 0x00, 0x4c, 0x69, 0x6e,
	0x75, 0x78, 0x20, 0x23, 0x30, 0x0a, 0x20, 0x20,
	0x20, 0x20, 0x00, 0x00, 0x00, 0xfd, 0x00, 0x3b,
	0x3d, 0x2f, 0x31, 0x07, 0x00, 0x0a, 0x20, 0x20,
	0x20, 0x20, 0x20, 0x20, 0x00, 0x00, 0x00, 0xfc,
	0x00, 0x4c, 0x69, 0x6e, 0x75, 0x78, 0x20, 0x58,
	0x47, 0x41, 0x0a, 0x20, 0x20, 0x20, 0x00, 0x55,
	},
	{
	0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00,
	0x31, 0xd8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x05, 0x16, 0x01, 0x03, 0x6d, 0x2c, 0x23, 0x78,
	0xea, 0x5e, 0xc0, 0xa4, 0x59, 0x4a, 0x98, 0x25,
	0x20, 0x50, 0x54, 0x00, 0x00, 0x00, 0x81, 0x80,
	0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
	0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x30, 0x2a,
	0x00, 0x98, 0x51, 0x00, 0x2a, 0x40, 0x30, 0x70,
	0x13, 0x00, 0xbc, 0x63, 0x11, 0x00, 0x00, 0x1e,
	0x00, 0x00, 0x00, 0xff, 0x00, 0x4c, 0x69, 0x6e,
	0x75, 0x78, 0x20, 0x23, 0x30, 0x0a, 0x20, 0x20,
	0x20, 0x20, 0x00, 0x00, 0x00, 0xfd, 0x00, 0x3b,
	0x3d, 0x3e, 0x40, 0x0b, 0x00, 0x0a, 0x20, 0x20,
	0x20, 0x20, 0x20, 0x20, 0x00, 0x00, 0x00, 0xfc,
	0x00, 0x4c, 0x69, 0x6e, 0x75, 0x78, 0x20, 0x53,
	0x58, 0x47, 0x41, 0x0a, 0x20, 0x20, 0x00, 0xa0,
	},
	{
	0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00,
	0x31, 0xd8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x05, 0x16, 0x01, 0x03, 0x6d, 0x37, 0x29, 0x78,
	0xea, 0x5e, 0xc0, 0xa4, 0x59, 0x4a, 0x98, 0x25,
	0x20, 0x50, 0x54, 0x00, 0x00, 0x00, 0xa9, 0x40,
	0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
	0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x48, 0x3f,
	0x40, 0x30, 0x62, 0xb0, 0x32, 0x40, 0x40, 0xc0,
	0x13, 0x00, 0x2b, 0xa0, 0x21, 0x00, 0x00, 0x1e,
	0x00, 0x00, 0x00, 0xff, 0x00, 0x4c, 0x69, 0x6e,
	0x75, 0x78, 0x20, 0x23, 0x30, 0x0a, 0x20, 0x20,
	0x20, 0x20, 0x00, 0x00, 0x00, 0xfd, 0x00, 0x3b,
	0x3d, 0x4a, 0x4c, 0x11, 0x00, 0x0a, 0x20, 0x20,
	0x20, 0x20, 0x20, 0x20, 0x00, 0x00, 0x00, 0xfc,
	0x00, 0x4c, 0x69, 0x6e, 0x75, 0x78, 0x20, 0x55,
	0x58, 0x47, 0x41, 0x0a, 0x20, 0x20, 0x00, 0x9d,
	},
	{
	0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00,
	0x31, 0xd8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x05, 0x16, 0x01, 0x03, 0x6d, 0x2b, 0x1b, 0x78,
	0xea, 0x5e, 0xc0, 0xa4, 0x59, 0x4a, 0x98, 0x25,
	0x20, 0x50, 0x54, 0x00, 0x00, 0x00, 0xb3, 0x00,
	0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
	0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x21, 0x39,
	0x90, 0x30, 0x62, 0x1a, 0x27, 0x40, 0x68, 0xb0,
	0x36, 0x00, 0xb5, 0x11, 0x11, 0x00, 0x00, 0x1e,
	0x00, 0x00, 0x00, 0xff, 0x00, 0x4c, 0x69, 0x6e,
	0x75, 0x78, 0x20, 0x23, 0x30, 0x0a, 0x20, 0x20,
	0x20, 0x20, 0x00, 0x00, 0x00, 0xfd, 0x00, 0x3b,
	0x3d, 0x40, 0x42, 0x0f, 0x00, 0x0a, 0x20, 0x20,
	0x20, 0x20, 0x20, 0x20, 0x00, 0x00, 0x00, 0xfc,
	0x00, 0x4c, 0x69, 0x6e, 0x75, 0x78, 0x20, 0x57,
	0x53, 0x58, 0x47, 0x41, 0x0a, 0x20, 0x00, 0x26,
	},
	{
	0x00, 0xff, 0xff, 0xff, 0xff, 0xff, 0xff, 0x00,
	0x31, 0xd8, 0x00, 0x00, 0x00, 0x00, 0x00, 0x00,
	0x05, 0x16, 0x01, 0x03, 0x6d, 0x32, 0x1c, 0x78,
	0xea, 0x5e, 0xc0, 0xa4, 0x59, 0x4a, 0x98, 0x25,
	0x20, 0x50, 0x54, 0x00, 0x00, 0x00, 0xd1, 0xc0,
	0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x01,
	0x01, 0x01, 0x01, 0x01, 0x01, 0x01, 0x02, 0x3a,
	0x80, 0x18, 0x71, 0x38, 0x2d, 0x40, 0x58, 0x2c,
	0x45, 0x00, 0xf4, 0x19, 0x11, 0x00, 0x00, 0x1e,
	0x00, 0x00, 0x00, 0xff, 0x00, 0x4c, 0x69, 0x6e,
	0x75, 0x78, 0x20, 0x23, 0x30, 0x0a, 0x20, 0x20,
	0x20, 0x20, 0x00, 0x00, 0x00, 0xfd, 0x00, 0x3b,
	0x3d, 0x42, 0x44, 0x0f, 0x00, 0x0a, 0x20, 0x20,
	0x20, 0x20, 0x20, 0x20, 0x00, 0x00, 0x00, 0xfc,
	0x00, 0x4c, 0x69, 0x6e, 0x75, 0x78, 0x20, 0x46,
	0x48, 0x44, 0x0a, 0x20, 0x20, 0x20, 0x00, 0x05,
	},
};

static u8 *edid_load(struct drm_connector *connector, char *name,
			char *connector_name)
{
	const struct firmware *fw;
	struct platform_device *pdev;
	u8 *fwdata = NULL, *edid, *new_edid;
	int fwsize, expected;
	int builtin = 0, err = 0;
	int i, valid_extensions = 0;
	bool print_bad_edid = !connector->bad_edid_counter || (drm_debug & DRM_UT_KMS);

	pdev = platform_device_register_simple(connector_name, -1, NULL, 0);
	if (IS_ERR(pdev)) {
		DRM_ERROR("Failed to register EDID firmware platform device "
		    "for connector \"%s\"\n", connector_name);
		err = -EINVAL;
		goto out;
	}

	err = request_firmware(&fw, name, &pdev->dev);
	platform_device_unregister(pdev);

	if (err) {
		i = 0;
		while (i < GENERIC_EDIDS && strcmp(name, generic_edid_name[i]))
			i++;
		if (i < GENERIC_EDIDS) {
			err = 0;
			builtin = 1;
			fwdata = generic_edid[i];
			fwsize = sizeof(generic_edid[i]);
		}
	}

	if (err) {
		DRM_ERROR("Requesting EDID firmware \"%s\" failed (err=%d)\n",
		    name, err);
		goto out;
	}

	if (fwdata == NULL) {
		fwdata = (u8 *) fw->data;
		fwsize = fw->size;
	}

	expected = (fwdata[0x7e] + 1) * EDID_LENGTH;
	if (expected != fwsize) {
		DRM_ERROR("Size of EDID firmware \"%s\" is invalid "
		    "(expected %d, got %d)\n", name, expected, (int) fwsize);
		err = -EINVAL;
		goto relfw_out;
	}

	edid = kmalloc(fwsize, GFP_KERNEL);
	if (edid == NULL) {
		err = -ENOMEM;
		goto relfw_out;
	}
	memcpy(edid, fwdata, fwsize);

	if (!drm_edid_block_valid(edid, 0, print_bad_edid)) {
		connector->bad_edid_counter++;
		DRM_ERROR("Base block of EDID firmware \"%s\" is invalid ",
		    name);
		kfree(edid);
		err = -EINVAL;
		goto relfw_out;
	}

	for (i = 1; i <= edid[0x7e]; i++) {
		if (i != valid_extensions + 1)
			memcpy(edid + (valid_extensions + 1) * EDID_LENGTH,
			    edid + i * EDID_LENGTH, EDID_LENGTH);
		if (drm_edid_block_valid(edid + i * EDID_LENGTH, i, print_bad_edid))
			valid_extensions++;
	}

	if (valid_extensions != edid[0x7e]) {
		edid[EDID_LENGTH-1] += edid[0x7e] - valid_extensions;
		DRM_INFO("Found %d valid extensions instead of %d in EDID data "
		    "\"%s\" for connector \"%s\"\n", valid_extensions,
		    edid[0x7e], name, connector_name);
		edid[0x7e] = valid_extensions;
		new_edid = krealloc(edid, (valid_extensions + 1) * EDID_LENGTH,
		    GFP_KERNEL);
		if (new_edid == NULL) {
			err = -ENOMEM;
			kfree(edid);
			goto relfw_out;
		}
		edid = new_edid;
	}

	DRM_INFO("Got %s EDID base block and %d extension%s from "
	    "\"%s\" for connector \"%s\"\n", builtin ? "built-in" :
	    "external", valid_extensions, valid_extensions == 1 ? "" : "s",
	    name, connector_name);

relfw_out:
	release_firmware(fw);

out:
	if (err)
		return ERR_PTR(err);

	return edid;
}

int drm_load_edid_firmware(struct drm_connector *connector)
{
	char *connector_name = drm_get_connector_name(connector);
	char *edidname = edid_firmware, *last, *colon;
	int ret;
	struct edid *edid;

	if (*edidname == '\0')
		return 0;

	colon = strchr(edidname, ':');
	if (colon != NULL) {
		if (strncmp(connector_name, edidname, colon - edidname))
			return 0;
		edidname = colon + 1;
		if (*edidname == '\0')
			return 0;
	}

	last = edidname + strlen(edidname) - 1;
	if (*last == '\n')
		*last = '\0';

	edid = (struct edid *) edid_load(connector, edidname, connector_name);
	if (IS_ERR_OR_NULL(edid))
		return 0;

	drm_mode_connector_update_edid_property(connector, edid);
	ret = drm_add_edid_modes(connector, edid);
	kfree(edid);

	return ret;
}