From c05e45ac7743c60a78ebee1b9e341fa5e089285d Mon Sep 17 00:00:00 2001 From: Hans de Goede Date: Fri, 30 Aug 2024 13:12:05 +0200 Subject: pipeline_handler: Add acquireDevice() function to mirror releaseDevice() libcamera always keeps all /dev/video# and /dev/v4l2_subdev# nodes for a pipeline open after enumerating the camera. This is a problem for the uvcvideo pipeline handler. Keeping /dev/video# open stops the UVC USB device from being able to enter runtime-suspend causing significant unnecessary power-usage. Add a stub acquireDevice() function to the PipelineHandler class which pipeline handlers can override. The uvcvideo pipeline handler will use this to delay opening /dev/video# until the device is acquired. This is a special case because the kernel uvcvideo driver powers on the USB device as soon as /dev/video# is opened. This behavior should *not* be copied by other pipeline handlers. Reviewed-by: Laurent Pinchart Reviewed-by: Harvey Yang Signed-off-by: Hans de Goede Signed-off-by: Laurent Pinchart --- include/libcamera/internal/pipeline_handler.h | 3 ++- 1 file changed, 2 insertions(+), 1 deletion(-) (limited to 'include') diff --git a/include/libcamera/internal/pipeline_handler.h b/include/libcamera/internal/pipeline_handler.h index cad5812f..597f7c3e 100644 --- a/include/libcamera/internal/pipeline_handler.h +++ b/include/libcamera/internal/pipeline_handler.h @@ -45,7 +45,7 @@ public: MediaDevice *acquireMediaDevice(DeviceEnumerator *enumerator, const DeviceMatch &dm); - bool acquire(); + bool acquire(Camera *camera); void release(Camera *camera); virtual std::unique_ptr generateConfiguration(Camera *camera, @@ -79,6 +79,7 @@ protected: virtual int queueRequestDevice(Camera *camera, Request *request) = 0; virtual void stopDevice(Camera *camera) = 0; + virtual bool acquireDevice(Camera *camera); virtual void releaseDevice(Camera *camera); CameraManager *manager_; -- cgit v1.2.1