Dell Inspiron with 2.5.75 and ACPI, backlight issues

[David G Hamblen]

With a Dell Inspiron 8100, running 2.5.75 with ACPI compiled in with sleep
states enabled, things work pretty much as expected except that the
backlight stays on when the system is first suspended to RAM.  Kind of
looks like the meaning of some bit is reversed.  It doesn't matter whether
I'm running X or not.

root#echo 3 > /proc/acpi/sleep
system suspends, screen goes white, backlight stays on.

<Hit power button>
 system comes up, backlight goes off!  At this point I can telnet (ssh) in
from another machine, etc; but the backlight stays off.  I can cycle the
sleep/power sequence many times, but the backlight stays off.

			Dave