Linux On My Samsung

Hi

Latest Maverick kernel, namely 2.6.35-24, prevents backlight control to work in my N150+ Samsung netbook.
I've manually modprobe'd the modules with debug=1 but I haven't noticed anything weird :?

To date, I've been using the modules installed with voRia kernels with latest Ubuntu kernels without problems.

Should I wait for the next voRia kernel or is there anything I can do to fix the issue? Right now I'm just booting with the voRia kernel, ignoring the kernel update.

Thanks!

Raúl

I have exactly the same problem for over a week on my N210 and the screen is now bleak.
Voria thank you if you could do something for us

Same problem for me.
No one of my attempts worked to solve so I just boot with the previous kernel.

Same problem on NF310.

Same problem on N220 and N150

Regards

Just filed a bug report: https://bugs.launchpad.net/samsung-tools/+bug/693071
Did anybody discover source code for building samsung-backlight?

Adding to the kernel's parameter list in your bootloader should do the trick.
For some reason, in 2.6.35-24 the ACPI driver starts feeling responsible for controlling the backlight.

In case of trouble when updating the kernel, backlight can also be controlled by manually writing numbers (0-7) to /sys/class/backlight/samsung/brightness (you may have to save several times to reach your target level of brightness).

Drake wrote:Adding

Code: Select all

acpi_backlight=vendor

to the kernel's parameter list in your bootloader should do the trick.
For some reason, in 2.6.35-24 the ACPI driver starts feeling responsible for controlling the backlight.

In case of trouble when updating the kernel, backlight can also be controlled by manually writing numbers (0-7) to /sys/class/backlight/samsung/brightness (you may have to save several times to reach your target level of brightness).

you know, for many peoples, it's more easy to install Windows !

I'm slightly aware of this fact.
Nevertheless, it might help some fanatic open source lover and Windows hater (I was told that Linux users sometimes match this character).

sometimes yes .... but they are fewer and fewer

Many many thanks Drake : ) works like a charm!

Here's how you change the kernel parameters. I am running Ubuntu 10.10 Netbook Edition on Samsung N210, so my bootloader is GRUB2.

Open the terminal...

1) Type "sudo nano /etc/default/grub" (replace nano with your favourite text editor, if needed)
2) Add "acpi_backlight=vendor" to the GRUB_CMDLINE_LINUX_DEFAULT parameters, so that...

GRUB_CMDLINE_LINUX_DEFAULT="quiet"

...or something similar becomes...

GRUB_CMDLINE_LINUX_DEFAULT="quiet acpi_backlight=vendor"

3) Close nano (CTRL+X) and save changes (Y)
4) Type "sudo update-grub2"
5) Type "sudo reboot"

In case you still have GRUB bootloader (instead of GRUB2), I believe you have to add "acpi_backlight=vendor" to /boot/grub/menu.lst, but unfortunately I don't have any system running with GRUB anywhere near, so I am unable to give you the full how-to. Google knows, I'm sure.

Thank you Drake and eth1cal for your "how to"...

but it doesn't work for me (N210 & classical ubuntu 10.10)
I will wait for again for few days and maybe make a downgrade toward ubuntu 10.04 LTS

Try setting it manually:
1) Type => The file should contain a single number (0-7).
2) Type a small number (replacing the old one), e.g. "1" and save several times (CTRL+O, ENTER).
=> Your screen should lower the brightness step by step.

Posting the output of the following command may also help to analyse your specific problem: Before wearing sun glasses, try adjusting the brightness at the GRUB screen.

At the same time, an update of Voria's deposits, has changed for the maximum luminosity (and it's better for me for now)

As you suggest, I can manually adjust the brightness lower step by step without any problems.

And here is the result of the code required:
acpi_video0 samsung


EDIT : I tried the eth1cal's method again and after the reboot, it works perfectly now, so a big thank you both for your help and your patience !

The presence of the "acpi_video0" directory is a strong indication of the ACPI driver problem solved by the fix mentioned above. After adding "acpi_backlight=vendor" to your kernel's paramter list it must not (well, it should not) exist.
You might want to check if applying the parameter was successful by running Output should look like If there is no output, the parameter was not applied successfully. You may want to check the GRUB_CMDLINE_LINUX_DEFAULT string, rerun update-grub2 and reboot first.
If there is an output... well, one step at a time. Feel free to post it.

EDIT: I am glad to read about your success.