From 85fdb3ff7d339097c564e11a8bd671cb2e80e28a Mon Sep 17 00:00:00 2001 From: Eino-Ville Talvala Date: Wed, 10 Jun 2015 14:58:32 -0700 Subject: [PATCH] Camera3: Document behavior of flush() corner cases. Document how HAL should operate when process_capture_request is called while a flush() call is active. Bug: 21506384 Change-Id: Ic1842add68123432e49914e83d8f7d5c13d6650d --- include/hardware/camera3.h | 14 ++++++++++++++ 1 file changed, 14 insertions(+) diff --git a/include/hardware/camera3.h b/include/hardware/camera3.h index d23bdf28..3ef6d6fa 100644 --- a/include/hardware/camera3.h +++ b/include/hardware/camera3.h @@ -2958,6 +2958,14 @@ typedef struct camera3_device_ops { * interruptible hardware blocks should be stopped, and any uninterruptible * blocks should be waited on. * + * flush() may be called concurrently to process_capture_request(), with the expectation that + * process_capture_request will return quickly and the request submitted in that + * process_capture_request call is treated like all other in-flight requests. Due to + * concurrency issues, it is possible that from the HAL's point of view, a + * process_capture_request() call may be started after flush has been invoked but has not + * returned yet. If such a call happens before flush() returns, the HAL should treat the new + * capture request like other in-flight pending requests (see #4 below). + * * More specifically, the HAL must follow below requirements for various cases: * * 1. For captures that are too late for the HAL to cancel/stop, and will be @@ -3002,6 +3010,12 @@ typedef struct camera3_device_ops { * 3.7. For fully-missing metadata, calling CAMERA3_MSG_ERROR_RESULT is sufficient, no * need to call process_capture_result with NULL metadata or equivalent. * + * 4. If a flush() is invoked while a process_capture_request() invocation is active, that + * process call should return as soon as possible. In addition, if a process_capture_request() + * call is made after flush() has been invoked but before flush() has returned, the + * capture request provided by the late process_capture_request call should be treated like + * a pending request in case #2 above. + * * flush() should only return when there are no more outstanding buffers or * requests left in the HAL. The framework may call configure_streams (as * the HAL state is now quiesced) or may issue new requests.