can't change brightness in Debian Lenny

**apemax** · 04-16-2010

hi im new here. I installed Debian Lenny on my old IBM thinkpad R40e but i can't change the brightness either with the Fn keys or with the brightness control debian has. i have searched around and it seems to be a problem with linux on IBM thinkpads but i don't know that much about this sort of thing so any help would be appreciated.

if you need any more info then just ask.

**nujinini** · 04-17-2010

Hello and Welcome!

This is a long shot but I guess there's nothing to lose.

Execute this and then see if you can change with hotkeys afterwards.

Code:

[User@localhost ~]$ xrandr --output LVDS --set BACKLIGHT_CONTROL native

**apemax** · 04-17-2010

this is what comes up when i execute that:

X Error of failed request: BadName (named color or font does not exist)
Major opcode of failed request: 156 (RANDR)
Minor opcode of failed request: 11 ()
Serial number of failed request: 17
Current serial number in output stream: 17

**nujinini** · 04-17-2010

If changing the brightness of your laptop monitor is that important to you, I suggest you might want to try other distros for the time being. I have a lenovo, same company that use to make IBMs. I was not also able change the screen brightness in Debian and Ubuntu. However, in Fedora, Mint, openSUSE, & Mandriva, I had better results.

I really loved my Lenny but had to let go of her

. My eyes can't take the glare anymore.

Good luck!

**apemax** · 04-19-2010

the reason i chose debian is that my computer only has 128MB of ram. do you know of any linux distro that is fairly easy to install like the ones you said but would run fairly well on 128MB of ram?

**GNU-Fan** · 04-19-2010

Before you abandon Debian, see if you can find a file like this (or similar):

Code:

/proc/acpi/video/VGA/LCD/brightness

If so, print its content with "cat" and write it in here.

**apemax** · 04-20-2010

i found a file like that here:

Code:

/proc/acpi/video/VID/LCD0/brightness

but when i try to open it with this:

Code:

cat brightness

it comes up: <not supported> i think.

i also tried to open it with a text editor but it came up when i first opened it: this file has changed. and when i open t again it was empty.

**GNU-Fan** · 04-20-2010

This "file" is not fit to be opened in a text editor as it is not really a file.
It is more like an interface to the hardware. But it is accessible from within the filesystem.

But its a pity that it wouldn't work in your system. If I "cat" it on my laptop, I get a couple of integer numbers. (0 40 100).
This means my laptop screen supports three settings for brightness.
A way to set it to 40% would then be to "write" the number 40 to this file (as root user):

Code:

echo "40" > /proc/acpi/video/VID/LCD0/brightness

But sadly your kernel does not seem to support this hardware. The other distributions have more current Linux kernels and therefore might know how to talk to the hardware correctly.
My recommendation would be to upgrade to Debian Unstable (if you are brave). And see if it supports the hardware better then.

**nujinini** · 04-20-2010

Linux.com :: Linux distros for older hardware

I googled and found this. You might want to check it out for some choices.

I have installed Mint 7 on old computers of friends that have fairly small specs and have not received any complaints from them to date. You might also want to give it a try too.

It's somewhat related to Debian somewhere up the line, if I'm not mistaken.

**apemax** · 04-22-2010

I think maybe DSL would be best for my pc but have had a look around and i am not sure how exactly to install it so i can dual boot it with windows. do you know?

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