From 334e9133dcdecb5d00d991332e05c7b80ae26578 Mon Sep 17 00:00:00 2001 From: Jan Grulich Date: Mon, 12 Feb 2024 14:41:05 +0100 Subject: [PATCH] Video capture PipeWire: add support for DMABuf buffer type Announce that we support SPA_DATA_DmaBuf and tell PipeWire not to map memory for us so we can handle it ourself, similar like we do in case of screen sharing. This fixes an issue when a camera is already in use by gstreamer (pipewiresrc), where DMABufs are used, and we try to share same camera and get no content, as PipeWire doesn't want to mmap DMABuf memory for us and we get NULL data pointers. Firefox bug: https://bugzilla.mozilla.org/show_bug.cgi?id=1876895 Bug: webrtc:15654 Change-Id: I788d8d12b2fcd5588329d7265e45b479f74bb628 Reviewed-on: https://webrtc-review.googlesource.com/c/src/+/338921 Commit-Queue: Jan Grulich Reviewed-by: Ilya Nikolaevskiy Reviewed-by: Per Kjellander Reviewed-by: Alexander Cooper Cr-Commit-Position: refs/heads/main@{#41826} --- .../linux/wayland/shared_screencast_stream.cc | 28 ------- modules/portal/pipewire_utils.h | 75 +++++++++++++++++++ .../linux/video_capture_pipewire.cc | 46 +++++++++--- 3 files changed, 110 insertions(+), 39 deletions(-) diff --git a/modules/desktop_capture/linux/wayland/shared_screencast_stream.cc b/modules/desktop_capture/linux/wayland/shared_screencast_stream.cc index 0c26e7a7d5..6998d655c2 100644 --- a/modules/desktop_capture/linux/wayland/shared_screencast_stream.cc +++ b/modules/desktop_capture/linux/wayland/shared_screencast_stream.cc @@ -14,7 +14,6 @@ #include #include #include -#include #include @@ -42,33 +41,6 @@ constexpr int CursorMetaSize(int w, int h) { constexpr PipeWireVersion kDmaBufModifierMinVersion = {0, 3, 33}; constexpr PipeWireVersion kDropSingleModifierMinVersion = {0, 3, 40}; -class ScopedBuf { - public: - ScopedBuf() {} - ScopedBuf(uint8_t* map, int map_size, int fd) - : map_(map), map_size_(map_size), fd_(fd) {} - ~ScopedBuf() { - if (map_ != MAP_FAILED) { - munmap(map_, map_size_); - } - } - - explicit operator bool() { return map_ != MAP_FAILED; } - - void initialize(uint8_t* map, int map_size, int fd) { - map_ = map; - map_size_ = map_size; - fd_ = fd; - } - - uint8_t* get() { return map_; } - - protected: - uint8_t* map_ = static_cast(MAP_FAILED); - int map_size_; - int fd_; -}; - class SharedScreenCastStreamPrivate { public: SharedScreenCastStreamPrivate(); diff --git a/modules/portal/pipewire_utils.h b/modules/portal/pipewire_utils.h index 8344a8cefb..c1327b85c9 100644 --- a/modules/portal/pipewire_utils.h +++ b/modules/portal/pipewire_utils.h @@ -11,6 +11,21 @@ #ifndef MODULES_PORTAL_PIPEWIRE_UTILS_H_ #define MODULES_PORTAL_PIPEWIRE_UTILS_H_ +#include +#include +#include +#include + +// static +struct dma_buf_sync { + uint64_t flags; +}; +#define DMA_BUF_SYNC_READ (1 << 0) +#define DMA_BUF_SYNC_START (0 << 2) +#define DMA_BUF_SYNC_END (1 << 2) +#define DMA_BUF_BASE 'b' +#define DMA_BUF_IOCTL_SYNC _IOW(DMA_BUF_BASE, 0, struct dma_buf_sync) + struct pw_thread_loop; namespace webrtc { @@ -32,6 +47,66 @@ class PipeWireThreadLoopLock { pw_thread_loop* const loop_; }; +// We should synchronize DMA Buffer object access from CPU to avoid potential +// cache incoherency and data loss. +// See +// https://01.org/linuxgraphics/gfx-docs/drm/driver-api/dma-buf.html#cpu-access-to-dma-buffer-objects +static bool SyncDmaBuf(int fd, uint64_t start_or_end) { + struct dma_buf_sync sync = {0}; + + sync.flags = start_or_end | DMA_BUF_SYNC_READ; + + while (true) { + int ret; + ret = ioctl(fd, DMA_BUF_IOCTL_SYNC, &sync); + if (ret == -1 && errno == EINTR) { + continue; + } else if (ret == -1) { + return false; + } else { + break; + } + } + + return true; +} + +class ScopedBuf { + public: + ScopedBuf() {} + ScopedBuf(uint8_t* map, int map_size, int fd, bool is_dma_buf = false) + : map_(map), map_size_(map_size), fd_(fd), is_dma_buf_(is_dma_buf) {} + ~ScopedBuf() { + if (map_ != MAP_FAILED) { + if (is_dma_buf_) { + SyncDmaBuf(fd_, DMA_BUF_SYNC_END); + } + munmap(map_, map_size_); + } + } + + explicit operator bool() { return map_ != MAP_FAILED; } + + void initialize(uint8_t* map, int map_size, int fd, bool is_dma_buf = false) { + map_ = map; + map_size_ = map_size; + is_dma_buf_ = is_dma_buf; + fd_ = fd; + + if (is_dma_buf_) { + SyncDmaBuf(fd_, DMA_BUF_SYNC_START); + } + } + + uint8_t* get() { return map_; } + + protected: + uint8_t* map_ = static_cast(MAP_FAILED); + int map_size_; + int fd_; + bool is_dma_buf_; +}; + } // namespace webrtc #endif // MODULES_PORTAL_PIPEWIRE_UTILS_H_ diff --git a/modules/video_capture/linux/video_capture_pipewire.cc b/modules/video_capture/linux/video_capture_pipewire.cc index 8af483636a..319824d3c5 100644 --- a/modules/video_capture/linux/video_capture_pipewire.cc +++ b/modules/video_capture/linux/video_capture_pipewire.cc @@ -178,8 +178,7 @@ int32_t VideoCaptureModulePipeWire::StartCapture( int res = pw_stream_connect( stream_, PW_DIRECTION_INPUT, node_id_, static_cast(PW_STREAM_FLAG_AUTOCONNECT | - PW_STREAM_FLAG_DONT_RECONNECT | - PW_STREAM_FLAG_MAP_BUFFERS), + PW_STREAM_FLAG_DONT_RECONNECT), params.data(), params.size()); if (res != 0) { RTC_LOG(LS_ERROR) << "Could not connect to camera stream: " @@ -312,11 +311,11 @@ void VideoCaptureModulePipeWire::OnFormatChanged(const struct spa_pod* format) { 0); } + const int buffer_types = + (1 << SPA_DATA_DmaBuf) | (1 << SPA_DATA_MemFd) | (1 << SPA_DATA_MemPtr); spa_pod_builder_add( &builder, SPA_PARAM_BUFFERS_buffers, SPA_POD_CHOICE_RANGE_Int(8, 1, 32), - SPA_PARAM_BUFFERS_dataType, - SPA_POD_CHOICE_FLAGS_Int((1 << SPA_DATA_MemFd) | (1 << SPA_DATA_MemPtr)), - 0); + SPA_PARAM_BUFFERS_dataType, SPA_POD_CHOICE_FLAGS_Int(buffer_types), 0); params.push_back( static_cast(spa_pod_builder_pop(&builder, &frame))); @@ -384,14 +383,15 @@ void VideoCaptureModulePipeWire::ProcessBuffers() { RTC_CHECK_RUNS_SERIALIZED(&capture_checker_); while (pw_buffer* buffer = pw_stream_dequeue_buffer(stream_)) { + spa_buffer* spaBuffer = buffer->buffer; struct spa_meta_header* h; h = static_cast( - spa_buffer_find_meta_data(buffer->buffer, SPA_META_Header, sizeof(*h))); + spa_buffer_find_meta_data(spaBuffer, SPA_META_Header, sizeof(*h))); struct spa_meta_videotransform* videotransform; videotransform = static_cast(spa_buffer_find_meta_data( - buffer->buffer, SPA_META_VideoTransform, sizeof(*videotransform))); + spaBuffer, SPA_META_VideoTransform, sizeof(*videotransform))); if (videotransform) { VideoRotation rotation = VideorotationFromPipeWireTransform(videotransform->transform); @@ -401,11 +401,35 @@ void VideoCaptureModulePipeWire::ProcessBuffers() { if (h->flags & SPA_META_HEADER_FLAG_CORRUPTED) { RTC_LOG(LS_INFO) << "Dropping corruped frame."; - } else { - IncomingFrame(static_cast(buffer->buffer->datas[0].data), - buffer->buffer->datas[0].chunk->size, - configured_capability_); + pw_stream_queue_buffer(stream_, buffer); + continue; } + + if (spaBuffer->datas[0].type == SPA_DATA_DmaBuf || + spaBuffer->datas[0].type == SPA_DATA_MemFd) { + ScopedBuf frame; + frame.initialize( + static_cast( + mmap(nullptr, + spaBuffer->datas[0].maxsize + spaBuffer->datas[0].mapoffset, + PROT_READ, MAP_PRIVATE, spaBuffer->datas[0].fd, 0)), + spaBuffer->datas[0].maxsize + spaBuffer->datas[0].mapoffset, + spaBuffer->datas[0].fd, spaBuffer->datas[0].type == SPA_DATA_DmaBuf); + + if (!frame) { + RTC_LOG(LS_ERROR) << "Failed to mmap the memory: " + << std::strerror(errno); + return; + } + + IncomingFrame( + SPA_MEMBER(frame.get(), spaBuffer->datas[0].mapoffset, uint8_t), + spaBuffer->datas[0].chunk->size, configured_capability_); + } else { // SPA_DATA_MemPtr + IncomingFrame(static_cast(spaBuffer->datas[0].data), + spaBuffer->datas[0].chunk->size, configured_capability_); + } + pw_stream_queue_buffer(stream_, buffer); } }