Brightness Control not working anymore, after last update

[psionMR]

Hy,

I use Samsung-Tools on my N210 and the brightness control always worked as it should (Fn+Up or down), but since the last update (ppa) it is not working anymore.

I use Ubuntu 11.10

Can you please correct this?

charly

[voria]

samsung-tools has nothing to do with brightness control (Fn-Up and Fn-Down).

Which other packages have you installed from the PPA?

[psionMR]

Thank's for the quick answer!

Additionally i have installed
- samsung labtop
- phc-intel

I hope this helps.

[voria]

Then your problem is probably caused by samsung-laptop, which also has been updated yesterday.

Try to add the option "acpi_backlight=vendor" to the kernel command line.
If the problem is not fixed, then remove samsung-laptop and test if the original version shipped with the ubuntu kernels works for you.

Alternatively you can switch back to the old control interface, easy-slow-down-manager + samsung-backlight.

[psionMR]

Thank's for the answer, but how do i get to the kernel command line?

[voria]

Open a terminal and edit the file '/etc/default/grub' as administrator:

Code: Select all

sudo gedit /etc/default/grub

Change the line:

Code: Select all

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

to:

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GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"

Save the file and exit.

Then, run this command to update grub with the new options:

Code: Select all

sudo update-grub

Finally, reboot.

[psionMR]

PERFECT!!!!!!!
works again!

thank you!!

[nanders]

sorry to bump an old topic, but I just like to mention this also helped me.

I'm using Linux Mint 13 on my N210 netbook, and my backlight control was not functioning well for quite a while, I think after an original kernel update. The slider responded to fn + up/down but the backlight didn't change. I tried this with the samsung-laptop and easy-slow-down-manager modules.

after months of adjusting backlight through the command line I found this post. I added 'acpi_backlight=vendor' to the kernel command line and it works again.

The initial brightness value after reboot is too low though, pressing fn+down once adjusts the brightness level to the slider value (but that doesn't bother me too much).

anyway, THANKS! your (voRia) work allows me to enjoy my netbook way better.

[Woulouf]

Thanks, this topic helped me to solve brightness control issue on my samsung n150

[brabus]

Sincerely THANK YOU for this simple yet effective guide.

Thanks to you, I managed to fix my backlight issue.

[sundial40]

I have a Samsung nc110 running Linux Mint 17 and have no way to adjust brightness when on battery. On battery screen is dark and just bearly readable. On AC power its excellent but cannot adjust and lower it.
I made the change to Grub suggested above on this thread but I still cannot adjust brightnedd with the fn key while on battery.

Any additional suggestions?

[Chrishas]

There was a change in a recent kernel which required adding this to your bootloader kernel parameters if you have an Intel card in order to control brightness:

video.use_native_backlight=0

Don't know if this would work for you as I only tried it on Arch and it solved my brightness issues.