I know it's possible. This machine used to have Debian Linux running on it.
Debian, by default, blacked out the screen if it wasn't used (i.e., no
keyboard/mouse action).  It actually turned the CRT off. I just don't know
enough about hardware drivers to know how they did it, and how it could
apply to NetBSD.

  - Jon

on 9/27/03 5:37 PM, Frederick Bruckman at fredb@immanent.net wrote:

> On Sat, 27 Sep 2003, Jon Fullmer wrote:
>=20
>> Has anyone out there gotten screenblank to work on a mac68k machine runn=
ing
>> NetBSD.  I=B9m running 1.6.1 on an SE/30, and every time I try to run it, =
it
>> gives me:
>>=20
>> Sep 27 11:38:00 hans screenblank: Can't set video on `/dev/ttyE0'
>> (Inappropriate ioctl for device)
>> Sep 27 11:38:00 hans screenblank: No frame buffer devices, exiting
>>=20
>> I can't seem to find any reference as to what the appropriate frame buff=
er
>> device would be.  Does this program simply not work on mac68k?  Is anyon=
e
>> using it, and if so, how?
>=20
> No, the wscons ioctls for blanking the screen are missing on mac68k.
> The *second* choice fallback, the framebuffer, doesn't exist on mac68k
> either.
>=20
> On i386, for example, you can turn off the raster to blank the screen
> by writing into a VGA register, and that's what wscons does. If you
> can do something like that with the mac68k hardware, no one's figured
> out how yet. I believe it should be possible to turn the brightness
> down to zero under software control on some of the Quadra's, at least.
> I think that's what "Silent Night", the Mac OS screensaver, does. I
> know you can adjust the brightness under software control, because
> there's a control panel for brightness.
>=20
> Frederick
>=20