From 7a36d05795fddf66f3ddaec710a8cace5af5623a Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Fri, 30 Aug 2024 13:12:07 +0200 Subject: pipeline: uvcvideo: Implement acquireDevice() + releaseDevice() The uvcvideo pipeline handler always keeps the uvcvideo /dev/video# node for a pipeline open after enumerating the camera. This is a problem for uvcvideo, as keeping the /dev/video# node open stops the underlying USB device and the USB bus controller from being able to enter runtime-suspend causing significant unnecessary power-usage. Implement acquireDevice() + releaseDevice(), openening /dev/video# on acquire and closing it on release to fix this. And make validate do a local video_->open() + close() around validate() when not open yet, to keep validate() working on unacquired cameras. Bug: https://bugs.libcamera.org/show_bug.cgi?id=168 Reviewed-by: Laurent Pinchart Signed-off-by: Hans de Goede Signed-off-by: Laurent Pinchart --- src/libcamera/pipeline/uvcvideo/uvcvideo.cpp | 54 ++++++++++++++++++++++++++-- 1 file changed, 51 insertions(+), 3 deletions(-) (limited to 'src') diff --git a/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp b/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp index 8a7409fc..e9faa1a9 100644 --- a/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp +++ b/src/libcamera/pipeline/uvcvideo/uvcvideo.cpp @@ -13,6 +13,7 @@ #include #include +#include #include #include @@ -48,6 +49,7 @@ public: const std::string &id() const { return id_; } + Mutex openLock_; std::unique_ptr video_; Stream stream_; std::map> formats_; @@ -93,6 +95,9 @@ private: const ControlValue &value); int processControls(UVCCameraData *data, Request *request); + bool acquireDevice(Camera *camera) override; + void releaseDevice(Camera *camera) override; + UVCCameraData *cameraData(Camera *camera) { return static_cast(camera->_d()); @@ -158,9 +163,29 @@ CameraConfiguration::Status UVCCameraConfiguration::validate() format.fourcc = data_->video_->toV4L2PixelFormat(cfg.pixelFormat); format.size = cfg.size; - int ret = data_->video_->tryFormat(&format); - if (ret) - return Invalid; + /* + * For power-consumption reasons video_ is closed when the camera is not + * acquired. Open it here if necessary. + */ + { + bool opened = false; + + MutexLocker locker(data_->openLock_); + + if (!data_->video_->isOpen()) { + int ret = data_->video_->open(); + if (ret) + return Invalid; + + opened = true; + } + + int ret = data_->video_->tryFormat(&format); + if (opened) + data_->video_->close(); + if (ret) + return Invalid; + } cfg.stride = format.planes[0].bpl; cfg.frameSize = format.planes[0].size; @@ -411,6 +436,23 @@ bool PipelineHandlerUVC::match(DeviceEnumerator *enumerator) return true; } +bool PipelineHandlerUVC::acquireDevice(Camera *camera) +{ + UVCCameraData *data = cameraData(camera); + + MutexLocker locker(data->openLock_); + + return data->video_->open() == 0; +} + +void PipelineHandlerUVC::releaseDevice(Camera *camera) +{ + UVCCameraData *data = cameraData(camera); + + MutexLocker locker(data->openLock_); + data->video_->close(); +} + int UVCCameraData::init(MediaDevice *media) { int ret; @@ -512,6 +554,12 @@ int UVCCameraData::init(MediaDevice *media) controlInfo_ = ControlInfoMap(std::move(ctrls), controls::controls); + /* + * Close to allow camera to go into runtime-suspend, video_ will be + * re-opened from acquireDevice() and validate(). + */ + video_->close(); + return 0; } -- cgit v1.2.1