NAME
smg —
Small Monochrome Graphics frame
buffer
SYNOPSIS
smg0 at vsbus0 csr 0x200f0000
wsdisplay* at smg?
DESCRIPTION
The smg is a monochrome frame buffer found
on-board most VAXstation 3100 systems.
The smg driver interfaces the frame buffer
with the wscons(4) console framework. It does not provide direct
device driver entry points but makes its functions available via the
internal
wsdisplay(4) interface.
When a color option board (either a
gpx(4) or a spx frame buffer) is installed, the
smg driver will not attach by default, since the
color option takes over the video connector on the back of the system.
However, the output signal pins are independent, and it is possible to
connect a monochrome video cable even if a color option board is installed.
To force the smg driver to attach in this case,
change the device flags to 1. It will however not be possible to use the
monochrome frame buffer as the OpenBSD console in
this case.