Subject: How is screenblank supposed to work?
To: None <>
From: Dave Huang <>
List: current-users
Date: 01/04/2001 00:10:26
I really want to turn off my macppc's screen (that white background
probably isn't too good for it :) when not in use, but Apple, in their
great wisdom, didn't include a real power switch on the thing (Apple
studio display monitor). So, screenblank sounds like the thing for me,
but the macppc ofb framebuffer device doesn't support the video on/off
ioctls. I did a bit of poking around in OpenFirmware, and found
ddc2ci-monitor-off and ddc2ci-monitor-on methods (Radeon AGP card in a
G4; dunno if those are present on other machines), so I hacked in
support for that...

Screenblank now knows how to turn off my monitor. Yay! But it never
turns it back on... Boo :( (unless I kill screenblank, then the monitor
comes back on). It looks like screenblank loops looking for the atime or
mtime of the keyboard or mouse devices to change... what's supposed to
update those in normal use? Typing on the keyboard and moving the mouse
don't do it. If I do something like "touch /dev/wskbd0", that wakes the
screen back up, but that's not how I want to turn on my monitor :)

P.S. how does usbhidctl work, and anyone know how to use it to fiddle
with the USB HID in the monitor? It'd be nice to be able to change the
brightness/contrast under NetBSD. Why is Apple so scared of real knobs
and buttons? :)
Name: Dave Huang     |   Mammal, mammal / their names are called /
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