This article mainly introduces the AIS camera request processing flow
The request processing flow, the specific process can be briefly described as, when the user opens the camera application to preview or clicks a photo operation
At this time, a photo request is triggered. The action is first passed through the capture of CameraDeviceSession or
The setRepeatingRequest method sends the request to the Camera Service through the Camera api v2 interface, and then
Camera Service internally sends this request to the CameraDevice::RequestThread thread for processing.
After entering the thread, it will finally pass the HIDL interface ICameraCaptureSession:processCaptureRequest_3_4
Send the request to the Provider, and then when the cameraProvider process receives the request, it will call the camera3_device_t function
The process_capture_request of the structure starts HAL's processing for this Request, which is performed by Qualcomm's on-board HAL
Responsible for implementation, the specific code flow is as follows:
The above process can be summarized in the following steps:
1. The request is managed by two threads in the V4L2Camera class, which are enqueueRequestBuffers and dequeueRequestBuffers;
2、enque