On Tue, Apr 19, 2011 at 12:14 PM, Anthony Campbell <a...@acampbell.org.uk> wrote: > 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. >
the right way would be to use sysctl. that said, i always do things the way you've done it :) > 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. > i'd check the kernel changelog or maybe the debian kernel package changelog and see if something was changed for sysfs and see why. i'm not sure whether this line of question is appropriate for that forum, but if it is, someone on debian-dev should know. (reading through the archives, they seem to be hard asses on topicality, so i'd do my research first). also, you could try to ask on irc in #kernel > 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. > iirc, this is stored in ram. i'll bet if you booted in the one kernel, and then did a shutdown -h and immediately powered up into the newer kernel, you'd notice a fail. that said, i think this is improper behavior. you didn't mention what version of debian you're running? ie, i don't think this happens onstable (than again, i'm only on .32, so...) > 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 think it is more in the kernel than in udev. (i think udev gets its info from sysfs and proc - that's probably a bad way of stating this though. it's fron the kernel at any rate) > 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, > this does sound like a bug. it's at least an issue with some default config. if you can, swap out discs and do a fresh install and see what happens. i'm pretty sure you'll notice the same thing. however, that would be the right thing to do before putting in a bug report (and it would be great of you to follow up on this - helps the community and all) -- To UNSUBSCRIBE, email to debian-user-requ...@lists.debian.org with a subject of "unsubscribe". Trouble? Contact listmas...@lists.debian.org Archive: http://lists.debian.org/BANLkTikSw=hysu2gaup0mqflbtsicf9...@mail.gmail.com
