[libcamera-devel] [PATCH v2 11/13] android: camera_device: Use CameraStream buffers

[Kieran Bingham]

Hello,

On 07/10/2020 09:05, Umang Jain wrote:
> Hi Jacopo,
> 
> On 10/6/20 8:14 PM, Jacopo Mondi wrote:
>> Now that CameraStream that require internal memory allocation
>> have been instrumented with a FrameBuffer pool, use them to create
>> intermediate buffers in the CameraDevice.
>>
>> Reviewed-by: Laurent Pinchart <laurent.pinchart at ideasonboard.com>
>> Signed-off-by: Jacopo Mondi <jacopo at jmondi.org>
>> ---
>>   src/android/camera_device.cpp | 51 ++++++++++++++++++++++++++++-------
>>   1 file changed, 41 insertions(+), 10 deletions(-)
>>
>> diff --git a/src/android/camera_device.cpp
>> b/src/android/camera_device.cpp
>> index ecdc0922e90b..b2fec7040038 100644
>> --- a/src/android/camera_device.cpp
>> +++ b/src/android/camera_device.cpp
>> @@ -1387,24 +1387,48 @@ int
>> CameraDevice::processCaptureRequest(camera3_capture_request_t
>> *camera3Reques
>>           descriptor->buffers[i].stream = camera3Buffers[i].stream;
>>           descriptor->buffers[i].buffer = camera3Buffers[i].buffer;
>>   -        /* Software streams are handled after hardware streams
>> complete. */
>> -        if (cameraStream->camera3Stream().format ==
>> HAL_PIXEL_FORMAT_BLOB)
>> -            continue;
>> -
>>           /*
>> -         * Create a libcamera buffer using the dmabuf descriptors of
>> -         * the camera3Buffer for each stream. The FrameBuffer is
>> -         * directly associated with the Camera3RequestDescriptor for
>> -         * lifetime management only.
>> +         * Inspect the camera stream type, create buffers opportunely
>> +         * and add them to the Request if required.
>>            */
>> -        FrameBuffer *buffer =
>> createFrameBuffer(*camera3Buffers[i].buffer);
>> +        FrameBuffer *buffer;
> I would not leave this un-initialize and initialize this to nullptr
> anyway (So that the `if (!buffer)` below is more tight). For now, buffer
> will get automatically get assigned to nullptr in the relevant
> switch-case-block on any errors though, so this is not really a blocker.
> 

Good spot.

Indeed, this doesn't get used uninitialised, as the
CameraStream::Type::Mapped will hit the continue statement, but I think
initialisign to nullptr would be safer code, protecting against any
future changes in here that might occur.

Agreed, not a blocker, but possibly a nice-to-have.
--
Kieran


> Thanks.
> Reviewed-by: Umang Jain <email at uajain.com>
>> +        switch (cameraStream->type()) {
>> +        case CameraStream::Type::Mapped:
>> +            /*
>> +             * Mapped streams don't need buffers added to the
>> +             * Request.
>> +             */
>> +            continue;
>> +
>> +        case CameraStream::Type::Direct:
>> +            /*
>> +             * Create a libcamera buffer using the dmabuf
>> +             * descriptors of the camera3Buffer for each stream and
>> +             * associate it with the Camera3RequestDescriptor for
>> +             * lifetime management only.
>> +             */
>> +            buffer = createFrameBuffer(*camera3Buffers[i].buffer);
>> +            descriptor->frameBuffers.emplace_back(buffer);
>> +            break;
>> +
>> +        case CameraStream::Type::Internal:
>> +            /*
>> +             * Get the frame buffer from the CameraStream internal
>> +             * buffer pool.
>> +             *
>> +             * The buffer has to be returned to the CameraStream
>> +             * once it has been processed.
>> +             */
>> +            buffer = cameraStream->getBuffer();
>> +            break;
>> +        }
>> +
>>           if (!buffer) {
>>               LOG(HAL, Error) << "Failed to create buffer";
>>               delete request;
>>               delete descriptor;
>>               return -ENOMEM;
>>           }
>> -        descriptor->frameBuffers.emplace_back(buffer);
>>             request->addBuffer(cameraStream->stream(), buffer);
>>       }
>> @@ -1476,6 +1500,13 @@ void CameraDevice::requestComplete(Request
>> *request)
>>               status = CAMERA3_BUFFER_STATUS_ERROR;
>>               continue;
>>           }
>> +
>> +        /*
>> +         * Return the FrameBuffer to the CameraStream now that we're
>> +         * done processing it.
>> +         */
>> +        if (cameraStream->type() == CameraStream::Type::Internal)
>> +            cameraStream->putBuffer(buffer);
>>       }
>>         /* Prepare to call back the Android camera stack. */
> 
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-- 
Regards
--
Kieran