Variable: comint-scroll-show-maximum-output

Controls how to scroll due to interpreter output.
This variable applies when point is at the end of the buffer
(either because it was originally there, or because
`comint-move-point-for-output' said to move it there)
and output from the subprocess is inserted.

Non-nil means scroll so that the window is full of text
and point is on the last line. A value of nil
means don't do anything special--scroll normally.

See also the variable `comint-move-point-for-output' and the function
`comint-postoutput-scroll-to-bottom'.
This variable is buffer-local in all Comint buffers.