media: docs-rst: media: Document broken frame handling in stream stop for CSI-2

Some CSI-2 transmitters will finish an ongoing frame whereas others will
not. Document that receiver drivers should not assume a particular
behaviour but to work in both cases.
Signed-off-by: Sakari Ailus <sakari.ailus@linux.intel.com>
Reviewed-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Mauro Carvalho Chehab <mchehab@s-opensource.com>

Documentation/media/kapi/csi2.rst

@@ -51,6 +51,16 @@ not active. Some transmitters do this automatically but some have to
 be explicitly programmed to do so, and some are unable to do so
 altogether due to hardware constraints.
 
+Stopping the transmitter
+^^^^^^^^^^^^^^^^^^^^^^^^
+
+A transmitter stops sending the stream of images as a result of
+calling the ``.s_stream()`` callback. Some transmitters may stop the
+stream at a frame boundary whereas others stop immediately,
+effectively leaving the current frame unfinished. The receiver driver
+should not make assumptions either way, but function properly in both
+cases.
+
 Receiver drivers
 ----------------