[libcamera-devel] [PATCH] cam: Add --monitor option
Umang Jain
email at uajain.com
Mon Jul 13 17:53:15 CEST 2020
Hi Niklas,
Thanks for the review.
On 7/13/20 7:35 PM, Niklas Söderlund wrote:
> Hi Umang,
>
> Thanks for your work.
>
> On 2020-07-13 12:11:28 +0000, Umang Jain wrote:
>> Add --monitor to monitor new hotplug and unplug camera events from
>> the CameraManager.
>>
>> Signed-off-by: Umang Jain <email at uajain.com>
> First off, for this patch.
>
> Reviewed-by: Niklas Söderlund <niklas.soderlund at ragnatech.se>
>
> When testing this patch to discover how far hotplug support have come I
> noticed some issues. I'm not aware if you know about them or not so I
> will describe them here.
>
> 1. Error message printed from cam
>
> When I run cam --monitor and physically unplug and then replug a USB
> UVC camera I get the following ERROR:
>
> $ cam --monitor
>
> * unplug camera *
> Camera Removed: Logitech Webcam C930e
> [465:45:06.515424906] [593092] ERROR V4L2 v4l2_videodevice.cpp:1117 /dev/video0[cap]: Unable to request 0 buffers: No such device
>
> * plug camera *
> Camera Added: Logitech Webcam C930e
>
> Would it be possible to not print the error when unplugging? I
> understand the IOCTL can never succeed as the vidoe device is gone
> but maybe we could avoid logging the error.
hmm, I am not sure if we can suppress logging that error without much
invasive changes.
On looking around, I noticed there couple of places where
V4L2VideoDevice::requestBuffers()
is called, with request buffer count = 0. This particular one, is being
called from releaseBuffers.
>
> 2. Qcam hits a delayed assert with hot-plug
>
> Once more the USB UVC camera is used.
>
> $ qcam
> [465:59:29.856991110] [599647] INFO IPAManager ipa_manager.cpp:136 libcamera is not installed. Adding '/home/neg/work/libcamera/libcamera/build/normal/src/ipa' to the IPA search path
> [465:59:29.858010955] [599647] INFO Camera camera_manager.cpp:283 libcamera v0.0.0+1602-7a13375c
> [465:59:29.870436670] [599649] INFO IPAProxy ipa_proxy.cpp:122 libcamera is not installed. Loading IPA configuration from '/home/neg/work/libcamera/libcamera/src/ipa/vimc/data'
> [465:59:36.255358189] [599647] INFO Camera camera.cpp:770 configuring streams: (0) 1920x1080-MJPEG
> Using software format conversion from MJPEG
> seq: 000000 bytesused: 151768 timestamp: 1677576692011000 fps: 0.00
> seq: 000001 bytesused: 157570 timestamp: 1677576715997000 fps: 41.69
> seq: 000002 bytesused: 158088 timestamp: 1677576751996000 fps: 27.78
> seq: 000003 bytesused: 158089 timestamp: 1677576783994000 fps: 31.25
> ....
> seq: 000080 bytesused: 167393 timestamp: 1677579347940000 fps: 31.25
> seq: 000081 bytesused: 167030 timestamp: 1677579383939000 fps: 27.78
> seq: 000082 bytesused: 167221 timestamp: 1677579415938000 fps: 31.25
> seq: 000083 bytesused: 166575 timestamp: 1677579447937000 fps: 31.25
> seq: 000084 bytesused: 165611 timestamp: 1677579483936000 fps: 27.78
> seq: 000085 bytesused: 166295 timestamp: 1677579515936000 fps: 31.25
>
> * unplug camera *
> Removing camera: Logitech Webcam C930e
> Failed to stop capture
>
> * wait a while *
>
> * close qcam *
> [465:59:47.587993893] [599647] ERROR V4L2 v4l2_videodevice.cpp:1117 /dev/video0[cap]: Unable to request 0 buffers: No such device
> [465:59:47.588042533] [599649] FATAL default event_dispatcher_poll.cpp:258 assertion "iter != notifiers_.end()" failed
> Backtrace:
> /home/neg/work/libcamera/libcamera/build/normal/src/qcam/../libcamera/libcamera.so(_ZN9libcamera19EventDispatcherPoll16processNotifiersERKSt6vectorI6pollfdSaIS2_EE+0x150) [0x7ffb28d9ae52]
> /home/neg/work/libcamera/libcamera/build/normal/src/qcam/../libcamera/libcamera.so(_ZN9libcamera19EventDispatcherPoll13processEventsEv+0x2b9) [0x7ffb28d9a75f]
> /home/neg/work/libcamera/libcamera/build/normal/src/qcam/../libcamera/libcamera.so(_ZN9libcamera6Thread4execEv+0x8a) [0x7ffb28de4396]
> /home/neg/work/libcamera/libcamera/build/normal/src/qcam/../libcamera/libcamera.so(_ZN9libcamera13CameraManager7Private3runEv+0x104) [0x7ffb28d4c0d4]
> /home/neg/work/libcamera/libcamera/build/normal/src/qcam/../libcamera/libcamera.so(_ZN9libcamera6Thread11startThreadEv+0xe5) [0x7ffb28de42ff]
> /home/neg/work/libcamera/libcamera/build/normal/src/qcam/../libcamera/libcamera.so(_ZSt13__invoke_implIvMN9libcamera6ThreadEFvvEPS1_JEET_St21__invoke_memfun_derefOT0_OT1_DpOT2_+0x67) [0x7ffb28de8c2b]
> /home/neg/work/libcamera/libcamera/build/normal/src/qcam/../libcamera/libcamera.so(_ZSt8__invokeIMN9libcamera6ThreadEFvvEJPS1_EENSt15__invoke_resultIT_JDpT0_EE4typeEOS6_DpOS7_+0x37) [0x7ffb28de8b6d]
> /home/neg/work/libcamera/libcamera/build/normal/src/qcam/../libcamera/libcamera.so(_ZNSt6thread8_InvokerISt5tupleIJMN9libcamera6ThreadEFvvEPS3_EEE9_M_invokeIJLm0ELm1EEEEvSt12_Index_tupleIJXspT_EEE+0x43) [0x7ffb28de8add]
> /home/neg/work/libcamera/libcamera/build/normal/src/qcam/../libcamera/libcamera.so(_ZNSt6thread8_InvokerISt5tupleIJMN9libcamera6ThreadEFvvEPS3_EEEclEv+0x18) [0x7ffb28de8a96]
> /home/neg/work/libcamera/libcamera/build/normal/src/qcam/../libcamera/libcamera.so(_ZNSt6thread11_State_implINS_8_InvokerISt5tupleIJMN9libcamera6ThreadEFvvEPS4_EEEEE6_M_runEv+0x1c) [0x7ffb28de8a7a]
> /usr/lib/libstdc++.so.6(+0xcfb74) [0x7ffb27582b74]
> /usr/lib/libpthread.so.0(+0x9422) [0x7ffb26f7d422]
> /usr/lib/libc.so.6(clone+0x43) [0x7ffb273cfbf3]
Yes, I am aware of QCam issue. I suppose you only had one camera(i.e.
UVC) on the system and trying to plug/unplug that?
Or did you have multiple ?
QCam still has some corners cases with one camera attached to the system
when I looked at it last time.
>
>> ---
>> src/cam/main.cpp | 24 ++++++++++++++++++++++++
>> src/cam/main.h | 1 +
>> 2 files changed, 25 insertions(+)
>>
>> diff --git a/src/cam/main.cpp b/src/cam/main.cpp
>> index 2512fe9..3488315 100644
>> --- a/src/cam/main.cpp
>> +++ b/src/cam/main.cpp
>> @@ -36,6 +36,8 @@ public:
>> void quit();
>>
>> private:
>> + void cameraAdded(std::shared_ptr<Camera> cam);
>> + void cameraRemoved(std::shared_ptr<Camera> cam);
>> int parseOptions(int argc, char *argv[]);
>> int prepareConfig();
>> int listControls();
>> @@ -115,6 +117,10 @@ int CamApp::init(int argc, char **argv)
>> ret = prepareConfig();
>> if (ret)
>> return ret;
>> + } else if (options_.isSet(OptMonitor)) {
>> + cm_->cameraAdded.connect(this, &CamApp::cameraAdded);
>> + cm_->cameraRemoved.connect(this, &CamApp::cameraRemoved);
>> + std::cout << "Monitoring new hotplug and unplug events..." << std::endl;
>> }
>>
>> loop_ = new EventLoop(cm_->eventDispatcher());
>> @@ -179,6 +185,8 @@ int CamApp::parseOptions(int argc, char *argv[])
>> "list-controls");
>> parser.addOption(OptListProperties, OptionNone, "List cameras properties",
>> "list-properties");
>> + parser.addOption(OptMonitor, OptionNone, "Monitor for hotplug and unplug camera events",
>> + "monitor");
>>
>> options_ = parser.parse(argc, argv);
>> if (!options_.valid())
>> @@ -293,6 +301,16 @@ int CamApp::infoConfiguration()
>> return 0;
>> }
>>
>> +void CamApp::cameraAdded(std::shared_ptr<Camera> cam)
>> +{
>> + std::cout << "Camera Added: " << cam->name() << std::endl;
>> +}
>> +
>> +void CamApp::cameraRemoved(std::shared_ptr<Camera> cam)
>> +{
>> + std::cout << "Camera Removed: " << cam->name() << std::endl;
>> +}
>> +
>> int CamApp::run()
>> {
>> int ret;
>> @@ -330,6 +348,12 @@ int CamApp::run()
>> return capture.run(loop_, options_);
>> }
>>
>> + if (options_.isSet(OptMonitor)) {
>> + ret = loop_->exec();
>> + if (ret)
>> + std::cout << "Failed to run monitor loop" << std::endl;
>> + }
>> +
>> return 0;
>> }
>>
>> diff --git a/src/cam/main.h b/src/cam/main.h
>> index 4a130d8..f61d288 100644
>> --- a/src/cam/main.h
>> +++ b/src/cam/main.h
>> @@ -15,6 +15,7 @@ enum {
>> OptInfo = 'I',
>> OptList = 'l',
>> OptListProperties = 'p',
>> + OptMonitor = 'm',
>> OptStream = 's',
>> OptListControls = 256,
>> };
>> --
>> 2.26.2
>>
>> _______________________________________________
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