NekoCWD/libcamera
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pipeline: uvcvideo: Implement acquireDevice() + releaseDevice()

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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 <laurent.pinchart@ideasonboard.com>
Signed-off-by: Hans de Goede <hdegoede@redhat.com>
Signed-off-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
This commit is contained in:
Hans de Goede 2024-08-30 13:12:07 +02:00 • committed by Laurent Pinchart
parent 11e396bf9f
commit 7a36d05795
1 changed files with 51 additions and 3 deletions
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54
src/libcamera/pipeline/uvcvideo/uvcvideo.cpp
View file

@ -13,6 +13,7 @@
#include <tuple>
#include <libcamera/base/log.h>
#include <libcamera/base/mutex.h>
#include <libcamera/base/utils.h>
#include <libcamera/camera.h>
@ -48,6 +49,7 @@ public:
const std::string &id() const { return id_; }
Mutex openLock_;
std::unique_ptr<V4L2VideoDevice> video_;
Stream stream_;
std::map<PixelFormat, std::vector<SizeRange>> 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<UVCCameraData *>(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;
}