[olpc-help] how is brightness controlled?

[Paul Fox]

i'm running 656, which was pre-installed on my very recent G1G1
machine.  the brightness keys on the keyboard have no effect.

i can modify the brightness using the /proc entry:
    echo 7 > /sys/class/backlight/dcon-bl/brightness 

the "showkey" program reports keypresses when i test with that,
and also, of course, the keyboard diagnostic says all keys are
fine.  xev shows that a KeymapNotify event is generated by the
keys, similar to the other function keys (which all work --
though i haven't test the volume keys.)

if this isn't a known problem, can someone point me to the rough
connection between the keyboard brightness keys and the kernel
(dcon?) brightness control?  if i knew where to start looking, i
might be able to debug this myself.


thanks...

(i've searched the bug database, but didn't find anything related --
at least, nothing at all recent.)

paul
=---------------------
 paul fox, pgf at foxharp.boston.ma.us (arlington, ma, where it's 30.9 degrees)