Backlight mystery - anyone shed light?

My HP laptop tends to boot with a dim screen. I can fix this with

echo 10 > /sys/devices/virtual/backlight/acpi_video0/brightness

which I run from /etc/rc,local.

It works well with all kernels up to 2.6.37. With 2.6.38 there is
usually no /sys/devices/virtual/backlight... so the above command
can't work.

What is really odd is that if I first boot with a 2.6.37 kernel and then
reboot with a 2.6.38 version, everything works correctly. The file I
need to modify is there and there is full brightness.

Is this perhaps something to do with udev? I've found ubuntu bug
reports describing somewhat similar problems but mostly with backlight
being too bright rather than too dim.

I would make a bug report if I knew which package was at fault. Can
anyone shed any light (literally)? It's an annoyance rather than a major
problem but I've been trying to figure it out for at least two weeks
wthout success,

Anthony


--
Anthony Campbell - ac@xxxxxxxxxxxxxxxx
Microsoft-free zone - Using Debian GNU/Linux
http://www.acampbell.org.uk - sample my ebooks at
http://www.smashwords.com/profile/view/acampbell


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