[PATCH 2/8] guides: application: Document Camera::metadataAvailable

[Jacopo Mondi]

Document the Camera::metadataAvailable signal in the application
developer guide as an opt-in feature to receive early metadata
notifications.

Signed-off-by: Jacopo Mondi <jacopo.mondi at ideasonboard.com>
---
 Documentation/guides/application-developer.rst | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/Documentation/guides/application-developer.rst b/Documentation/guides/application-developer.rst
index 25beb55d99a3..560bb4464497 100644
--- a/Documentation/guides/application-developer.rst
+++ b/Documentation/guides/application-developer.rst
@@ -357,6 +357,14 @@ Signals and Slots`_) to connect events with callbacks to handle them.
 The ``Camera`` device emits two signals that applications can connect to in
 order to execute callbacks on frame completion events.
 
+The ``Camera::metadataAvailable`` signal notifies applications of the
+availability of metadata results before a request completes. Receiving
+notification about metadata availability allows application to fast-track
+handling of metadata results before all the image buffers in a request are
+ready. The full list of metadata results associated with a Request is anyway
+available at request complete time, and receiving notifications for early
+metadata availability is an optional feature for applications.
+
 The ``Camera::bufferCompleted`` signal notifies applications that a buffer with
 image data is available. Receiving notifications about the single buffer
 completion event allows applications to implement partial request completion
-- 
2.47.1