[PATCH v5 3/3] libcamera: software_isp: Clean up pending requests on stop

[Hans de Goede]

Hi,

On 21-Oct-24 3:37 PM, Milan Zamazal wrote:
> PipelineHandler::stop() calls stopDevice() method to perform pipeline
> specific cleanup and then completes waiting requests.  If any queued
> requests remain, an assertion error is raised.
> 
> Software ISP stores request buffers in
> SimpleCameraData::conversionQueue_ and queues them as V4L2 signals
> bufferReady.  stopDevice() cleanup forgets to clean up the buffers and
> their requests from conversionQueue_, possibly resulting in the
> assertion error.  This patch fixes the omission.
> 
> The problem wasn't very visible when
> SimplePipelineHandler::kNumInternalBuffers (the number of buffers
> allocated in V4L2) was equal to the number of buffers exported from
> software ISP.  But when the number of the exported buffers was increased
> by one in commit abe2ec64f9e4e97bbdfe3a50372611bd7b5315c2, the assertion
> error started pop up in some environments.  Increasing the number of the
> buffers much more, e.g. to 9, makes the problem very reproducible.
> 
> Each pipeline uses its own mechanism to track the requests to clean up
> and it can't be excluded that similar omissions are present in other
> places.  But there is no obvious way to make a common cleanup for all
> the pipelines (except for doing it instead of raising the assertion
> error, which is probably undesirable, in order not to hide incomplete
> pipeline specific cleanups).
> 
> Bug: https://bugs.libcamera.org/show_bug.cgi?id=234
> Signed-off-by: Milan Zamazal <mzamazal at redhat.com>

Thanks, patch looks good to me:

Reviewed-by: Hans de Goede <hdegoede at redhat.com>

Regards,

Hans




> ---
>  src/libcamera/pipeline/simple/simple.cpp | 10 ++++++++++
>  1 file changed, 10 insertions(+)
> 
> diff --git a/src/libcamera/pipeline/simple/simple.cpp b/src/libcamera/pipeline/simple/simple.cpp
> index f3a6b1635..6b1121c34 100644
> --- a/src/libcamera/pipeline/simple/simple.cpp
> +++ b/src/libcamera/pipeline/simple/simple.cpp
> @@ -288,6 +288,7 @@ public:
>  	};
>  	std::queue<RequestOutputs> conversionQueue_;
>  	bool useConversion_;
> +	void clearIncompleteRequests();
>  
>  	std::unique_ptr<Converter> converter_;
>  	std::unique_ptr<SoftwareIsp> swIsp_;
> @@ -897,6 +898,14 @@ void SimpleCameraData::conversionOutputDone(FrameBuffer *buffer)
>  		pipe->completeRequest(request);
>  }
>  
> +void SimpleCameraData::clearIncompleteRequests()
> +{
> +	while (!conversionQueue_.empty()) {
> +		pipe()->cancelRequest(conversionQueue_.front().request);
> +		conversionQueue_.pop();
> +	}
> +}
> +
>  void SimpleCameraData::ispStatsReady(uint32_t frame, uint32_t bufferId)
>  {
>  	swIsp_->processStats(frame, bufferId,
> @@ -1406,6 +1415,7 @@ void SimplePipelineHandler::stopDevice(Camera *camera)
>  
>  	video->bufferReady.disconnect(data, &SimpleCameraData::bufferReady);
>  
> +	data->clearIncompleteRequests();
>  	data->conversionBuffers_.clear();
>  
>  	releasePipeline(data);