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feat(capture/windows): hook APIs to avoid output reparenting that bre…
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…aks DDA
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@cgutman
cgutman committed Jan 12, 2025
1 parent 6f989d2 commit 42daad2
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1 change: 1 addition & 0 deletions .codeql-prebuild-cpp-Windows.sh
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Expand Up @@ -11,6 +11,7 @@ dependencies=(
"mingw-w64-ucrt-x86_64-cmake"
"mingw-w64-ucrt-x86_64-cppwinrt"
"mingw-w64-ucrt-x86_64-curl-winssl"
"mingw-w64-ucrt-x86_64-MinHook"
"mingw-w64-ucrt-x86_64-miniupnpc"
"mingw-w64-ucrt-x86_64-nlohmann-json"
"mingw-w64-ucrt-x86_64-nodejs"
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1 change: 1 addition & 0 deletions .github/workflows/CI.yml
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Expand Up @@ -885,6 +885,7 @@ jobs:
mingw-w64-ucrt-x86_64-cppwinrt
mingw-w64-ucrt-x86_64-curl-winssl
mingw-w64-ucrt-x86_64-graphviz
mingw-w64-ucrt-x86_64-MinHook
mingw-w64-ucrt-x86_64-miniupnpc
mingw-w64-ucrt-x86_64-nlohmann-json
mingw-w64-ucrt-x86_64-nodejs
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2 changes: 1 addition & 1 deletion cmake/dependencies/common.cmake
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Expand Up @@ -28,7 +28,7 @@ include_directories(SYSTEM ${MINIUPNP_INCLUDE_DIRS})
# ffmpeg pre-compiled binaries
if(NOT DEFINED FFMPEG_PREPARED_BINARIES)
if(WIN32)
set(FFMPEG_PLATFORM_LIBRARIES mfplat ole32 strmiids mfuuid vpl)
set(FFMPEG_PLATFORM_LIBRARIES mfplat ole32 strmiids mfuuid vpl MinHook)
elseif(UNIX AND NOT APPLE)
set(FFMPEG_PLATFORM_LIBRARIES numa va va-drm va-x11 X11)
endif()
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1 change: 1 addition & 0 deletions docs/building.md
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Expand Up @@ -90,6 +90,7 @@ dependencies=(
"mingw-w64-ucrt-x86_64-curl-winssl"
"mingw-w64-ucrt-x86_64-doxygen" # Optional, for docs... better to install official Doxygen
"mingw-w64-ucrt-x86_64-graphviz" # Optional, for docs
"mingw-w64-ucrt-x86_64-MinHook"
"mingw-w64-ucrt-x86_64-miniupnpc"
"mingw-w64-ucrt-x86_64-nlohmann-json"
"mingw-w64-ucrt-x86_64-nodejs"
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168 changes: 47 additions & 121 deletions src/platform/windows/display_base.cpp
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Expand Up @@ -9,10 +9,22 @@
#include <boost/algorithm/string/join.hpp>
#include <boost/process/v1.hpp>

#include <MinHook.h>

// We have to include boost/process/v1.hpp before display.h due to WinSock.h,
// but that prevents the definition of NTSTATUS so we must define it ourself.
typedef long NTSTATUS;

// Definition from the WDK's d3dkmthk.h
typedef enum _D3DKMT_GPU_PREFERENCE_QUERY_STATE: DWORD {
D3DKMT_GPU_PREFERENCE_STATE_UNINITIALIZED, ///< The GPU preference isn't initialized.
D3DKMT_GPU_PREFERENCE_STATE_HIGH_PERFORMANCE, ///< The highest performing GPU is preferred.
D3DKMT_GPU_PREFERENCE_STATE_MINIMUM_POWER, ///< The minimum-powered GPU is preferred.
D3DKMT_GPU_PREFERENCE_STATE_UNSPECIFIED, ///< A GPU preference isn't specified.
D3DKMT_GPU_PREFERENCE_STATE_NOT_FOUND, ///< A GPU preference isn't found.
D3DKMT_GPU_PREFERENCE_STATE_USER_SPECIFIED_GPU ///< A specific GPU is preferred.
} D3DKMT_GPU_PREFERENCE_QUERY_STATE;

#include "display.h"
#include "misc.h"
#include "src/config.h"
Expand Down Expand Up @@ -329,111 +341,6 @@ namespace platf::dxgi {
return capture_e::ok;
}

bool
set_gpu_preference_on_self(int preference) {
// The GPU preferences key uses app path as the value name.
WCHAR sunshine_path[MAX_PATH];
GetModuleFileNameW(NULL, sunshine_path, ARRAYSIZE(sunshine_path));

WCHAR value_data[128];
swprintf_s(value_data, L"GpuPreference=%d;", preference);

auto status = RegSetKeyValueW(HKEY_CURRENT_USER,
L"Software\\Microsoft\\DirectX\\UserGpuPreferences",
sunshine_path,
REG_SZ,
value_data,
(wcslen(value_data) + 1) * sizeof(WCHAR));
if (status != ERROR_SUCCESS) {
BOOST_LOG(error) << "Failed to set GPU preference: "sv << status;
return false;
}

BOOST_LOG(info) << "Set GPU preference: "sv << preference;
return true;
}

bool
validate_and_test_gpu_preference(const std::string &display_name, bool verify_frame_capture) {
std::string cmd = "tools\\ddprobe.exe";

// We start at 1 because 0 is automatic selection which can be overridden by
// the GPU driver control panel options. Since ddprobe.exe can have different
// GPU driver overrides than Sunshine.exe, we want to avoid a scenario where
// autoselection might work for ddprobe.exe but not for us.
for (int i = 1; i < 5; i++) {
// Run the probe tool. It returns the status of DuplicateOutput().
//
// Arg format: [GPU preference] [Display name] [--verify-frame-capture]
HRESULT result;
std::vector<std::string> args = { std::to_string(i), display_name };
try {
if (verify_frame_capture) {
args.emplace_back("--verify-frame-capture");
}
result = bp::system(cmd, bp::args(args), bp::std_out > bp::null, bp::std_err > bp::null);
}
catch (bp::process_error &e) {
BOOST_LOG(error) << "Failed to start ddprobe.exe: "sv << e.what();
return false;
}

BOOST_LOG(info) << "ddprobe.exe " << boost::algorithm::join(args, " ") << " returned 0x"
<< util::hex(result).to_string_view();

// E_ACCESSDENIED can happen at the login screen. If we get this error,
// we know capture would have been supported, because DXGI_ERROR_UNSUPPORTED
// would have been raised first if it wasn't.
if (result == S_OK || result == E_ACCESSDENIED) {
// We found a working GPU preference, so set ourselves to use that.
if (set_gpu_preference_on_self(i)) {
return true;
}
else {
return false;
}
}
}

// If no valid configuration was found, return false
return false;
}

// On hybrid graphics systems, Windows will change the order of GPUs reported by
// DXGI in accordance with the user's GPU preference. If the selected GPU is a
// render-only device with no displays, DXGI will add virtual outputs to the
// that device to avoid confusing applications. While this works properly for most
// applications, it breaks the Desktop Duplication API because DXGI doesn't proxy
// the virtual DXGIOutput to the real GPU it is attached to. When trying to call
// DuplicateOutput() on one of these virtual outputs, it fails with DXGI_ERROR_UNSUPPORTED
// (even if you try sneaky stuff like passing the ID3D11Device for the iGPU and the
// virtual DXGIOutput from the dGPU). Because the GPU preference is once-per-process,
// we spawn a helper tool to probe for us before we set our own GPU preference.
bool
probe_for_gpu_preference(const std::string &display_name) {
static bool set_gpu_preference = false;

// If we've already been through here, there's nothing to do this time.
if (set_gpu_preference) {
return true;
}

// Try probing with different GPU preferences and verify_frame_capture flag
if (validate_and_test_gpu_preference(display_name, true)) {
set_gpu_preference = true;
return true;
}

// If no valid configuration was found, try again with verify_frame_capture == false
if (validate_and_test_gpu_preference(display_name, false)) {
set_gpu_preference = true;
return true;
}

// If neither worked, return false
return false;
}

/**
* @brief Tests to determine if the Desktop Duplication API can capture the given output.
* @details When testing for enumeration only, we avoid resyncing the thread desktop.
Expand Down Expand Up @@ -506,6 +413,27 @@ namespace platf::dxgi {
return false;
}

/**
* @brief Hook for NtGdiDdDDIGetCachedHybridQueryValue() from win32u.dll.
* @param gpuPreference A pointer to the location where the preference will be written.
* @return Always STATUS_SUCCESS if valid arguments are provided.
*/
NTSTATUS
__stdcall NtGdiDdDDIGetCachedHybridQueryValueHook(D3DKMT_GPU_PREFERENCE_QUERY_STATE *gpuPreference) {
// By faking a cached GPU preference state of D3DKMT_GPU_PREFERENCE_STATE_UNSPECIFIED, this will
// prevent DXGI from performing the normal GPU preference resolution that looks at the registry,
// power settings, and the hybrid adapter DDI interface to pick a GPU. Instead, we will not be
// bound to any specific GPU. This will prevent DXGI from performing output reparenting (moving
// outputs from their true location to the render GPU), which breaks DDA.
if (gpuPreference) {
*gpuPreference = D3DKMT_GPU_PREFERENCE_STATE_UNSPECIFIED;
return 0; // STATUS_SUCCESS
}
else {
return STATUS_INVALID_PARAMETER;
}
}

int
display_base_t::init(const ::video::config_t &config, const std::string &display_name) {
std::once_flag windows_cpp_once_flag;
Expand All @@ -515,13 +443,22 @@ namespace platf::dxgi {

typedef BOOL (*User32_SetProcessDpiAwarenessContext)(DPI_AWARENESS_CONTEXT value);

auto user32 = LoadLibraryA("user32.dll");
auto f = (User32_SetProcessDpiAwarenessContext) GetProcAddress(user32, "SetProcessDpiAwarenessContext");
if (f) {
f(DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE_V2);
{
auto user32 = LoadLibraryA("user32.dll");
auto f = (User32_SetProcessDpiAwarenessContext) GetProcAddress(user32, "SetProcessDpiAwarenessContext");
if (f) {
f(DPI_AWARENESS_CONTEXT_PER_MONITOR_AWARE_V2);
}

FreeLibrary(user32);
}

FreeLibrary(user32);
{
// We aren't calling MH_Uninitialize(), but that's okay because this hook lasts for the life of the process
MH_Initialize();
MH_CreateHookApi(L"win32u.dll", "NtGdiDdDDIGetCachedHybridQueryValue", (void *) NtGdiDdDDIGetCachedHybridQueryValueHook, nullptr);
MH_EnableHook(MH_ALL_HOOKS);
}
});

// Get rectangle of full desktop for absolute mouse coordinates
Expand All @@ -530,11 +467,6 @@ namespace platf::dxgi {

HRESULT status;

// We must set the GPU preference before calling any DXGI APIs!
if (!probe_for_gpu_preference(display_name)) {
BOOST_LOG(warning) << "Failed to set GPU preference. Capture may not work!"sv;
}

status = CreateDXGIFactory1(IID_IDXGIFactory1, (void **) &factory);
if (FAILED(status)) {
BOOST_LOG(error) << "Failed to create DXGIFactory1 [0x"sv << util::hex(status).to_string_view() << ']';
Expand Down Expand Up @@ -1101,12 +1033,6 @@ namespace platf {

BOOST_LOG(debug) << "Detecting monitors..."sv;

// We must set the GPU preference before calling any DXGI APIs!
const auto output_name { display_device::map_output_name(config::video.output_name) };
if (!dxgi::probe_for_gpu_preference(output_name)) {
BOOST_LOG(warning) << "Failed to set GPU preference. Capture may not work!"sv;
}

// We sync the thread desktop once before we start the enumeration process
// to ensure test_dxgi_duplication() returns consistent results for all GPUs
// even if the current desktop changes during our enumeration process.
Expand Down

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