I find it interesting that in the console the dimming works. I thought that on
PPC the console used the framebuffer. Another notable thing is that while in
X, the dimming doesn't work, but when I switch to one of the VTs, the screen
brightness is adjusted to what it should have been in X.
Ah ? What do you mean by "dimming" ? blanking ? or backlight control ?
OK, the F1 and F2 keys on my keyboard have little "brighter"/"dimmer"
icons on them. When I press them when running X on 2.4.25, the screen
brightness changes. So for me, that's "dimming." I believe that it's the
"backlight control" that does this. When I press the "dimmer" button
enough (8 times, I think), then the backlight turns totally off, and I
can't see anything on the screen. For me that's "blanking" in this
context. It's true that something else (X, I think) will kind of blank
the screen, but the backlight stays lit. I noticed this when I closed
the lid to make the iBook sleep, but the backlight stayed on, warming
the keyboard. I then noticed the same problem with the dimmer keys.
Could be some crap done by the X driver ... It's notoriously allergic to
fbdev's ... I'll have to double check.
It probably is. But it's strange because I use all the same software
except the kernel to get this behavior. So there's something with the
kernel / X interface that has changed, either for 2.6 or the way Debian
builds 2.6. I have a hard time with this because there are so many
interactions: is it the PMU? The APM emulation? X driver? Kernel
driver? I don't have a good idea about how these things interact.