libcamera: pipeline_handler: extend documentation for configureStreams()

Extend the documentation to explicitly state that the pipeline handler
implementations are responsible for validating that the requested
configuration can be exactly satisfied by the hardware.

Signed-off-by: Niklas Söderlund <niklas.soderlund@ragnatech.se>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>

src/libcamera/pipeline_handler.cpp

@@ -136,6 +136,14 @@ PipelineHandler::~PipelineHandler()
  * is the Camera class which will receive configuration to apply from the
  * application.
  *
+ * Each pipeline handler implementation is responsible for validating
+ * that the configuration requested in \a config can be achieved
+ * exactly. Any difference in pixel format, frame size or any other
+ * parameter shall result in the -EINVAL error being returned, and no
+ * change in configuration being applied to the pipeline. If
+ * configuration of a subset of the streams can't be satisfied, the
+ * whole configuration is considered invalid.
+ *
  * \return 0 on success or a negative error code on error.
  */