1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
|
// Copyright (c) 2013 The Chromium Authors. All rights reserved.
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#include "base/x11/edid_parser_x11.h"
#include <X11/extensions/Xrandr.h>
#include <X11/Xatom.h>
#include <X11/Xlib.h>
#include "base/hash.h"
#include "base/message_loop/message_loop.h"
#include "base/strings/string_util.h"
#include "base/sys_byteorder.h"
namespace {
// Returns 64-bit persistent ID for the specified manufacturer's ID and
// product_code_hash, and the index of the output it is connected to.
// |output_index| is used to distinguish the displays of the same type. For
// example, swapping two identical display between two outputs will not be
// treated as swap. The 'serial number' field in EDID isn't used here because
// it is not guaranteed to have unique number and it may have the same fixed
// value (like 0).
int64 GetID(uint16 manufacturer_id,
uint32 product_code_hash,
uint8 output_index) {
return ((static_cast<int64>(manufacturer_id) << 40) |
(static_cast<int64>(product_code_hash) << 8) | output_index);
}
bool IsRandRAvailable() {
int randr_version_major = 0;
int randr_version_minor = 0;
static bool is_randr_available = XRRQueryVersion(
base::MessagePumpX11::GetDefaultXDisplay(),
&randr_version_major, &randr_version_minor);
return is_randr_available;
}
} // namespace
namespace base {
bool GetEDIDProperty(XID output, unsigned long* nitems, unsigned char** prop) {
if (!IsRandRAvailable())
return false;
Display* display = base::MessagePumpX11::GetDefaultXDisplay();
static Atom edid_property = XInternAtom(
base::MessagePumpX11::GetDefaultXDisplay(),
RR_PROPERTY_RANDR_EDID, false);
bool has_edid_property = false;
int num_properties = 0;
Atom* properties = XRRListOutputProperties(display, output, &num_properties);
for (int i = 0; i < num_properties; ++i) {
if (properties[i] == edid_property) {
has_edid_property = true;
break;
}
}
XFree(properties);
if (!has_edid_property)
return false;
Atom actual_type;
int actual_format;
unsigned long bytes_after;
XRRGetOutputProperty(display,
output,
edid_property,
0, // offset
128, // length
false, // _delete
false, // pending
AnyPropertyType, // req_type
&actual_type,
&actual_format,
nitems,
&bytes_after,
prop);
DCHECK_EQ(XA_INTEGER, actual_type);
DCHECK_EQ(8, actual_format);
return true;
}
bool GetDisplayId(XID output_id, size_t output_index, int64* display_id_out) {
unsigned long nitems = 0;
unsigned char* prop = NULL;
if (!GetEDIDProperty(output_id, &nitems, &prop))
return false;
bool result =
GetDisplayIdFromEDID(prop, nitems, output_index, display_id_out);
XFree(prop);
return result;
}
bool GetDisplayIdFromEDID(const unsigned char* prop,
unsigned long nitems,
size_t output_index,
int64* display_id_out) {
uint16 manufacturer_id = 0;
std::string product_name;
// ParseOutputDeviceData fails if it doesn't have product_name.
ParseOutputDeviceData(prop, nitems, &manufacturer_id, &product_name);
// Generates product specific value from product_name instead of product code.
// See crbug.com/240341
uint32 product_code_hash = product_name.empty() ?
0 : base::Hash(product_name);
if (manufacturer_id != 0) {
// An ID based on display's index will be assigned later if this call
// fails.
*display_id_out = GetID(
manufacturer_id, product_code_hash, output_index);
return true;
}
return false;
}
bool ParseOutputDeviceData(const unsigned char* prop,
unsigned long nitems,
uint16* manufacturer_id,
std::string* human_readable_name) {
// See http://en.wikipedia.org/wiki/Extended_display_identification_data
// for the details of EDID data format. We use the following data:
// bytes 8-9: manufacturer EISA ID, in big-endian
// bytes 54-125: four descriptors (18-bytes each) which may contain
// the display name.
const unsigned int kManufacturerOffset = 8;
const unsigned int kManufacturerLength = 2;
const unsigned int kDescriptorOffset = 54;
const unsigned int kNumDescriptors = 4;
const unsigned int kDescriptorLength = 18;
// The specifier types.
const unsigned char kMonitorNameDescriptor = 0xfc;
if (manufacturer_id) {
if (nitems < kManufacturerOffset + kManufacturerLength) {
LOG(ERROR) << "too short EDID data: manifacturer id";
return false;
}
*manufacturer_id =
*reinterpret_cast<const uint16*>(prop + kManufacturerOffset);
#if defined(ARCH_CPU_LITTLE_ENDIAN)
*manufacturer_id = base::ByteSwap(*manufacturer_id);
#endif
}
if (!human_readable_name)
return true;
human_readable_name->clear();
for (unsigned int i = 0; i < kNumDescriptors; ++i) {
if (nitems < kDescriptorOffset + (i + 1) * kDescriptorLength)
break;
const unsigned char* desc_buf =
prop + kDescriptorOffset + i * kDescriptorLength;
// If the descriptor contains the display name, it has the following
// structure:
// bytes 0-2, 4: \0
// byte 3: descriptor type, defined above.
// bytes 5-17: text data, ending with \r, padding with spaces
// we should check bytes 0-2 and 4, since it may have other values in
// case that the descriptor contains other type of data.
if (desc_buf[0] == 0 && desc_buf[1] == 0 && desc_buf[2] == 0 &&
desc_buf[4] == 0) {
if (desc_buf[3] == kMonitorNameDescriptor) {
std::string found_name(
reinterpret_cast<const char*>(desc_buf + 5), kDescriptorLength - 5);
TrimWhitespaceASCII(found_name, TRIM_TRAILING, human_readable_name);
break;
}
}
}
// Verify if the |human_readable_name| consists of printable characters only.
for (size_t i = 0; i < human_readable_name->size(); ++i) {
char c = (*human_readable_name)[i];
if (!isascii(c) || !isprint(c)) {
human_readable_name->clear();
LOG(ERROR) << "invalid EDID: human unreadable char in name";
return false;
}
}
return true;
}
} // namespace base
|
