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OMGitsUGOD

Member

Registered: 2009-08-27

Posts: 21

Brightness on Lenovo 3000 N100

Hi!
I know there are lots of posts about the issue of setting brightness  on laptop screens, and some posts suggest it's a bug in the 2.6.30 kernel, but I'm not sure if this bug concerns my system? I have a Lenovo 3000 N100 with the Intel Mobile 945GM chipset and with my previous installation (Ubuntu 9.04), adjusting brightness with Fn-F10 and Fn -F11 worked out-of-the-box.

I was looking for ways of doing this from the command line, but none of the methods I could find works. For example;

xbacklight

returns

 No outputs have backlight property

when running KMS, and if I remove KMS it returns "nan".

At various places it was suggested that

xrandr --output LVDS --set BACKLIGHT_CONTROL legacy

would do the trick. This trick does something good as now I'm able to use xbacklight -get and xbacklight -set Y (not running KMS), without getting any error messages. Nothing happens to the screen though.

I also checked my Fn-[FX] buttons with keycode, and as it turns out all Fn-[Fx] combinations (which should do something) are detected except for Fn-F11 which is supposed to increase the brightness level?

What's wrong here, and how is Ubuntu able to get all this working out-of-the box?

Regards

Last edited by OMGitsUGOD (2009-09-03 08:29:53)

OMGitsUGOD

Member

Registered: 2009-08-27

Posts: 21

Re: Brightness on Lenovo 3000 N100

No clues? I have investigated the Fn-buttons a little further since I want to use them to suspend, hibernate etc.  using acpid. But when I push the eg the sleep button nothing happens and I get no messages in /var/log/messages.log, so acpi doesn't recognize it as an event?

I tried xev for checking my Fn-keys and this is what I got from my sleep-button:

KeyPress event, serial 36, synthetic NO, window 0x2600001,
    root 0xfc, subw 0x0, time 11938462, (59,-228), root:(893,79),
    state 0x0, keycode 150 (keysym 0x1008ff2f, XF86Sleep), same_screen YES,
    XLookupString gives 0 bytes: 
    XmbLookupString gives 0 bytes: 
    XFilterEvent returns: False

All the other Fn-combinations give me similar outputs, except for the brighten-button (Fn-F11) which seems to go completely undetected by the kernel.

I know these are multiple problems, but all hints are appreciated!

combuster

Member

From: Serbia

Registered: 2008-09-30

Posts: 711

Website

Re: Brightness on Lenovo 3000 N100

Ubuntu doesn't have kms enabled by default (nor arch) but if kms is enabled backlight control via Fn+ keys doesn't work. In the latest git snapshot of xf86-video-intel driver (2.8.99.901) this issue has been fixed and right now I'm able to change the backlight level via Fn+Up/Down...

I forgot to mention that I'm running 2.6.31-rc9 kernel and that related changes in the acpi and intel in the kernel made this possible...

In the meanwhile you could append acpi_brightness=vendor as a kernel parametar in your menu.lst...  We already discussed this issue on this forum...

Last edited by combuster (2009-09-09 21:41:38)

OMGitsUGOD

Member

Registered: 2009-08-27

Posts: 21

Re: Brightness on Lenovo 3000 N100

Thanks for the answer. I just wrote a long reply but somehow I managed to remove it, I'll do a shorter verison instead.

I know this has been discussed elsewhere, I mean my first post starts with me saying just that. I was unsure however if that discussion was applicable to my system, hence my post. I know that KMS isn't enabled by default thats why I wrote about it in my initial post , trying both with and without KMS. The acpi_brightness=vendor was the first thing I tried, but I noticed no difference so I removed it again, and that was part of the reason why I posted this here, instead of in other posts.

Anyway, I found out that I can manipulate the file /proc/acpi/video/GFX0/LCD/brightness in order to manually change the brightness. So I wrote a script that steps up and down in brighness level, so everything works ok now. Actually after your post I tried adding that acpi_brightness=vendor in my menu.lst again, and that breaks my script and the Fn-up/down buttons still doesn't work. The /proc/acpi/video/GFX0/LCD/brightness file now just says "<not applicable>", or something similar.   

A final weird thing is that when I manually change the brightness to somthing other than 100, the Fn-up/down buttons start to work, but in a buggy way. They just step either down to 0 or up to 100 without intermediate steps. Once the brightness is back at 100, the buttons stop working again. I tried to fix this by adding my scripts to handler.sh in /etc/acpi/, but it still works weird. It is as though something else is also listening on these buttons?

Hmm...this wasn't so short after all, but anyhow things work ok so I'll just be patient and wait to see what happens when the new kernel hits the repos.
Thanks again.

combuster

Member

From: Serbia

Registered: 2008-09-30

Posts: 711

Website

Re: Brightness on Lenovo 3000 N100

With 2.6.31 and xf86-video-intel-git from aur your brightness keys will work ok... You could compile the kernel and video driver yourself if you don't want to wait...

OMGitsUGOD

Member

Registered: 2009-08-27

Posts: 21

Re: Brightness on Lenovo 3000 N100

Yeah I know, but I really should work...:)

OMGitsUGOD

Member

Registered: 2009-08-27

Posts: 21

Re: Brightness on Lenovo 3000 N100

I'll try to make an attempt to bring this topic back from the dead. The thing is I still have problem with my backlight. It works, say every fourth boot and then I'm able to change backlight via /proc/acpi/video/GFX0/LCD/brightness or via /sys/class/backlight/acpivideo0/brightness. When it's not woking /sys/class/backlight/ is empty and  /proc/acpi/video/GFX0/LCD/brightness says <not supported>. At times, say once every fifty boots, the screen is very dark, you could hardly make see what goes on on the screen, when I reboot the screen is alright again.

I'm on kernel 2.6.31.5-1 and using xf86-video-intel 2.8.1-1. Where should I look to get this resolved.

monk

Member

Registered: 2008-05-25

Posts: 8

Re: Brightness on Lenovo 3000 N100

I had the same issue with my lenovo 3000 C200 and i am able to modify the screen brightness (at least with the gnome brightness applett) after renaming video.ko:

http://www.thinkwiki.org/wiki/Problem_w … ss_buttons

OMGitsUGOD

Member

Registered: 2009-08-27

Posts: 21

Re: Brightness on Lenovo 3000 N100

Thank's for the tip, but it didnt't help though. A lot of Ubuntu people seems to have the problem in Karmic,
https://bugs.launchpad.net/ubuntu/+sour … bug/406515
Hope something will come out of it.
Thanks again.