Screen brightness does not change on Toshiba Satellite in Karmic

[rahulpatilb]

I had the same problem on my Acer 4736 laptop having GM45 chipset, 4500MHD. I tried out adding 'nomodeset acpi_backlight=vendor' to the GRUB_CMDLINE_LINUX_DEFAULT line. After rebooting the brightness keys started to work, though the keys were revered. Unfortunately the brightness resets after subsequent reboots and some times stops working.

Anyone has any idea what could be the problem? Thanks in advance

[im2061]

Go to System > Preference > Power Management
Under "Display", "Set display brightness to:", choose the brightness you prefer.

[apstanto]

I am also using Ubuntu 9.10 (upgraded from 9.04) and do not have the file /etc/default/grub. I want to do "xrandr --output LVDS --set BACKLIGHT_CONTROL native". Any suggestions?

[Cabs21]

I had this same issue with 9.04 and when I upgraded to 9.10 it still didnt work. I was ecstatic that the problem seemed to fix itself when I went from 32-bit to 64-bit 9.10 with a fresh install I could adjust the brightness with the Fn+F8/F9 key combos. However after I updated my software the problem resurfaced and I can no longer see any results from me changing the brightness in power management or or the Fn key combos.

[Vignesh S]

OMG!! I was having the same problem on my Toshiba Satellite T110 (which is pretty much the same thing is that T135) and after I applied your fix, IT WORKS!!! I seriously owe you one

[chellrose]

Okay, I've now got brightness controls working perfectly. I used the fix discussed in this post: http://ubuntuforums.org/showthread.php?t=121742

Basically, all you do is edit /etc/default/grub You add 'nomodeset acpi_backlight=vendor' to the GRUB_CMDLINE_LINUX_DEFAULT line.

Everything works as expected, except for some reason the lowest brightness setting turns the screen off completely. I don't know whether or not this is a feature or a bug. Either way, I'm satisfied with this fix. I hope it works for you guys too.

That fix works in GNOME... I can set brightness with the brightness applet or with the Fn keys. Unfortunately, KDE3 (which I use much more often) seems to be ignoring that fix. The link in eOgas' post takes me to a completely unrelated thread about an incorrect Ubuntu installation. Does anyone have a suggestion for getting brightness to work in KDE?

Thanks.

[Viaxl]

THANKS DUDE! You saved my ***!
even this didn't work at first. I'm using Grub2. I append that line to the GRUB_CMDLINE_LINUX_DEFAULT there was no effect.

then after a lot of reading I figured out the update-grub doesn't work to me at all. it just doesn't change the \boot\grub\grub.cfg (I found this problem because I can't update Kernel too. changing in menu.lst has no effect either)

so i edit the grub.cfg... ignoring "DO NOT EDIT THIS FILE", append "nomodeset acpi_backlight=vendor" , so the entry changes to:

menuentry “Ubuntu, Linux 2.6.31-14-generic” {
        recordfail=1
        if [ -n ${have_grubenv} ]; then save_env recordfail; fi
    set quiet=1
    insmod ext2
    set root=(hd0,1)
    search –no-floppy –fs-uuid –set c6a96e39-7f93-4663-b35f-8df4d30b0764
    linux /boot/vmlinuz-2.6.31-14-generic root=UUID=c6a96e39-7f93-4663-b35f-8df4d30b0764 ro quiet splash nomodeset acpi_backlight=vendor
    initrd    /boot/initrd.img-2.6.31-14-generic
}

reboot, it works! both in gnome and KDE!
you saved my eyes too~
hope this could help someone, even though i'm not sure what i am doing. i'm such a newbie to linux, maybe someone could explain to me why? is it a bug?

[Ganda1f]

I am running Ubuntu 9.04 on Acer laptop, and I had to edit /boot/grub/menu.lst and do the changes specified by slakkie.

Once those changes are done you need to run the command

sudo update-grub

and reboot to get the brightness working properly. Just that the keys are reversed. I don't think that is a major problem.

[peepingtom]

o edit: sry, bad advice

[Cauda_Draconis]

It's not working on my Toshiba Satellite A100, either. Changing display brightness never has. I tried eOgas' grub fix, but all that did was get the computer to recognize that it can't change the brightness (the tooltip on the brightness applet in the panel says "Cannot get laptop panel brightness").