[EXT] Re: [PATCH] android: camera_device: Fix camera blocked issue when stopping capture

[Anle Pan]

Hi Umang Jain,

this issue was random(around 1/10), and can be reproduced by single run below cts test:
	./cts-tradefed run commandAndExit cts --abi arm64-v8a -m CtsMediaPlayerTestCases -t android.media.player.cts.MediaPlayerTest#testRecordedVideoPlayback90

•	3 times configuring streams in this Test:
1)  2 streams:   (0) 320x240-NV12 (1) 1280x720-YUYV:   capture several frames on stream1
2)  3 streams:   (0) 320x240-NV12 (1) 320x240-NV12 (2) 1280x720-YUYV: will capture on stream0 and stream2 at the same time
3)  2 streams:   (0) 320x240-NV12 (1) 1280x720-YUYV:   capture several frames on stream1

•	when single run the test several times and met fail. When digging the log, can find that the current failed is caused by the abnormal complete of the previous PASS test in step3, which is the situation described in my patch.

Best Regards
Anle Pan

-----Original Message-----
From: Umang Jain <umang.jain at ideasonboard.com> 
Sent: 2024年3月5日 16:27
To: Anle Pan <anle.pan at nxp.com>; libcamera-devel at lists.libcamera.org
Cc: Hui Fang <hui.fang at nxp.com>
Subject: [EXT] Re: [PATCH] android: camera_device: Fix camera blocked issue when stopping capture

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Hi Anle Pan, Hui Fang

On 04/03/24 3:05 pm, Anle Pan wrote:
> The issue occurs when stopping capture soon after starting capture.

Can you describe the issue/use case in more detail? It's really hard to infer from one line.
>
> In this case, no frame get from the device, the related capture 
> request has been pushed to the queue descriptors_, but the 
> queuedRequests_ was still empty due to no requests will be queue to 
> the device since the stream will be stopped soon,

I don't get it how is this possible? Since processCaptureRequest() will push the request in the descriptors_ queue along with queuing the request to the camera.

How will the call path be interleaved /before/ processCaptureRequest() returns? Possibly we need more details on what you are trying to do, before reviewing the code here. Is this related to CTS ?
> so there will be no camera->requestComplete called later, then the 
> descriptors_ can not pop normally, this will cause the pending if we 
> want to start capture next time.
>
> To fix the issue, ensure the descriptors_ is empty after the camera 
> device is stopped.
>
> Signed-off-by: Anle Pan <anle.pan at nxp.com>
> ---
>   src/android/camera_device.cpp | 5 ++++-
>   1 file changed, 4 insertions(+), 1 deletion(-)
>
> diff --git a/src/android/camera_device.cpp 
> b/src/android/camera_device.cpp index 25cedd44..d452992d 100644
> --- a/src/android/camera_device.cpp
> +++ b/src/android/camera_device.cpp
> @@ -433,8 +433,11 @@ void CameraDevice::flush()
>   void CameraDevice::stop()
>   {
>       MutexLocker stateLock(stateMutex_);
> -     if (state_ == State::Stopped)
> +     if (state_ == State::Stopped) {
> +             MutexLocker descriptorsLock(descriptorsMutex_);
> +             descriptors_ = {};
>               return;
> +     }
>
>       camera_->stop();
>