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
|
// Copyright 2022 The Chromium Authors
// Use of this source code is governed by a BSD-style license that can be
// found in the LICENSE file.
#ifdef UNSAFE_BUFFERS_BUILD
// TODO(crbug.com/351564777): Remove this and convert code to safer constructs.
#pragma allow_unsafe_buffers
#endif
#include "ui/display/win/audio_edid_scan.h"
#include <objbase.h>
#include <oleauto.h>
#include <string.h>
#include "base/logging.h"
#include "base/win/scoped_bstr.h"
#include "base/win/scoped_variant.h"
#include "base/win/wmi.h"
#include "ui/display/util/edid_parser.h"
namespace display {
namespace win {
namespace {
// Use 'wmi_services' to execute the WmiGetMonitorRawEEdidV1Block method of
// 'get_edid_block' for the 'path' and 'id'. The result will be EDID data
// which will be appended to the 'edid_blob'. A single device (or monitor)
// will have one 'path' with multiple 'id' values. To get all 'id' values
// for a given 'path', start with 'id' of zero and stop when 'id' cannot be
// read.
bool AppendBlock(Microsoft::WRL::ComPtr<IWbemServices>& wmi_services,
Microsoft::WRL::ComPtr<IWbemClassObject>& get_edid_block,
base::win::ScopedVariant& path,
int id,
std::vector<uint8_t>& edid_blob) {
base::win::ScopedVariant block_id(id);
if (FAILED(get_edid_block->Put(L"BlockId", 0, block_id.AsInput(), 0)))
return false;
Microsoft::WRL::ComPtr<IWbemClassObject> out_params;
HRESULT hr = wmi_services->ExecMethod(
V_BSTR(path.ptr()),
base::win::ScopedBstr(L"WmiGetMonitorRawEEdidV1Block").Get(), 0, nullptr,
get_edid_block.Get(), &out_params, nullptr);
if (FAILED(hr))
return false;
base::win::ScopedVariant block_type;
if (FAILED(
out_params->Get(L"BlockType", 0, block_type.Receive(), nullptr, 0))) {
return false;
}
base::win::ScopedVariant block_content;
if (FAILED(out_params->Get(L"BlockContent", 0, block_content.Receive(),
nullptr, 0))) {
return false;
}
// Block type: 1=EDID base block, 2=EDID block map, 255=Other
constexpr int allowed_types[] = {1, 2, 255};
const int found_type = V_I4(block_type.ptr());
if (std::none_of(std::begin(allowed_types), std::end(allowed_types),
[found_type](int i) { return i == found_type; })) {
return false;
}
if (block_content.type() != (VT_ARRAY | VT_UI1))
return false;
SAFEARRAY* array = V_ARRAY(block_content.ptr());
if (SafeArrayGetDim(array) != 1)
return false;
long lower_bound = 0;
long upper_bound = 0;
SafeArrayGetLBound(array, 1, &lower_bound);
SafeArrayGetUBound(array, 1, &upper_bound);
if (lower_bound || upper_bound <= lower_bound)
return false;
uint8_t* block = nullptr;
SafeArrayAccessData(array, reinterpret_cast<void**>(&block));
edid_blob.insert(edid_blob.end(), block, block + upper_bound + 1);
SafeArrayUnaccessData(array);
return true;
}
} // namespace
uint32_t ScanEdidBitstreams() {
// The WMI service allows the querying of monitor-type devices which report
// Extended Display Identification Data (EDID). The WMI service can be
// queried for a list of COM objects which represent the "paths" which
// are associated with individual EDID devices. Querying each of those
// paths using the WmiGetMonitorRawEEdidV1Block method returns the EDID
// blocks for those devices. We query the extended blocks which contain
// the Short Audio Descriptor (SAD), and parse them to obtain a bitmask
// indicating which audio content is supported. The mask consists of
// AudioParameters::Format flags. If multiple EDID devices are present,
// the intersection of flags is reported.
Microsoft::WRL::ComPtr<IWbemServices> wmi_services =
base::win::CreateWmiConnection(true, L"ROOT\\WMI");
if (!wmi_services)
return 0;
Microsoft::WRL::ComPtr<IWbemClassObject> get_edid_block;
if (!base::win::CreateWmiClassMethodObject(
wmi_services.Get(), L"WmiMonitorDescriptorMethods",
L"WmiGetMonitorRawEEdidV1Block", &get_edid_block)) {
return 0;
}
Microsoft::WRL::ComPtr<IEnumWbemClassObject> wmi_enumerator;
HRESULT hr = wmi_services->CreateInstanceEnum(
base::win::ScopedBstr(L"WmiMonitorDescriptorMethods").Get(),
WBEM_FLAG_FORWARD_ONLY, nullptr, &wmi_enumerator);
if (FAILED(hr))
return 0;
bool first = true;
uint32_t bitstream_mask = 0;
while (true) {
Microsoft::WRL::ComPtr<IWbemClassObject> class_object;
ULONG items_returned = 0;
hr = wmi_enumerator->Next(WBEM_INFINITE, 1, &class_object, &items_returned);
if (FAILED(hr) || hr == WBEM_S_FALSE || items_returned == 0)
break;
// Path refers to the display for which EDID will be read.
base::win::ScopedVariant path;
class_object->Get(L"__PATH", 0, path.Receive(), nullptr, nullptr);
// Reading a single EDID block at a time, assemble all blocks for the path.
int block_id = 0;
std::vector<uint8_t> edid_blob;
while (AppendBlock(wmi_services, get_edid_block, path, block_id, edid_blob))
block_id++;
if (first) {
first = false;
bitstream_mask =
display::EdidParser(std::move(edid_blob)).audio_formats();
} else {
bitstream_mask &=
display::EdidParser(std::move(edid_blob)).audio_formats();
}
}
return bitstream_mask;
}
} // namespace win
} // namespace display
|
