The available list of readout patterns for a given instrument mode are available in the ETC in a drop-down menu on the Detector Setup tab. Only the readout patterns allowed for science are provided as options. Invalid combinations of Readout pattern and Subarray produce a warning on the Detector Setup tab and are disallowed.

Instrument readout patterns

See also: Understanding Exposure Times

MIRI Detector Readout Overview

NIRCam Detector Readout Patterns

NIRISS Detector Readout Patterns

NIRSpec Detector Readout Modes and Patterns