Brightness level issues

Question

About two updates ago, everything with brightness was working perfect!

But since then, the Function keys for brightness(Fn + up and Fn + down) are not working... I mean the brightness reduces only till 1 step using the keys and after that its locked.

Also, when I go to the brightness settings and reduce the brightness, this is what happens:

The brightness is reduced. I close the settings.
When I start brightness settings again, the brightness is at the set level BUT the arrow on the scroller/scale is at full!
I click anywhere on the scale, the brightness suddenly increases to full and then starts reducing.

Also the brightness level is not remembered after restarting from Hibernation and/or suspend. What is wrong all of a sudden? I am using Ubuntu 12.04 LTS with Unity 3D on Samsung NP-RV 509

And I have Samsung slow down manager and Samsung tools installed. (They make the function keys and stuff work on Samsung hardware properly. It is similar to the software provided by Samsung for windows.)

Please share the content or output of the following commands/files to better help us troubleshoot your problem (instructions in this answer): file(s): command(s): lsmod — ish, Aug 21 '12 at 20:20
yeah its normal English(US)...but how does that make a diff?? the Fn+ up/down works till one step of reducing brightness...which means the system knows its a brightness key...but it does not reduce it! — Nirmik, Aug 22 '12 at 17:40
@izx...here is the pastebin- http://paste.ubuntu.com/1159696/ — Nirmik, Aug 22 '12 at 18:05
This looks like a problem with the samsung_laptop module, you should file a bug with them. — ish, Aug 26 '12 at 16:43

score 1 · Answer 1 · edited Apr 13 '17 at 12:23

1

Changing a line in /etc/default/grub fixed my problems for me (I'm running Ubuntu 12.04 on a Samsung QX411). You could try it.

EDIT: To test below without completely updating grub, reboot and hit e when you see the grub menu. Then just add the acpi_osi= after the quiet splash boot option and execute (cntl+x, I think)

Change:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash"

to:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi="

Then do sudo update-grub and reboot

Here's a reference for the fix: What does the kernel boot parameter "set acpi_osi=Linux" do?

edited Apr 13 '17 at 12:23

Community

1

answered Aug 28 '12 at 20:08

Ian B.

3,513

umm...how does grub hav to do anything here? – Nirmik Aug 30 '12 at 15:34
it's a kernel issue. You have to pass the right commands to the kernel. acpi_osi= basically makes the kernel tell the bios it's not running linux. I'll find the references and edit my answer – Ian B. Aug 30 '12 at 20:01
there is no file like grub in there....there is grub.ucf-old and a burg file...*NOTE-i was using burg earlier when i had dual boot – Nirmik Aug 31 '12 at 18:37
I don't know anything about burg, but do you know if you're running grub? If you are, see my edits above to test if the boot option will even work. On my computer, grub.ucf-old looks like just a backup file for the /etc/default/grub, so you may be able to just rename... however, you should probably be VERY careful and know exactly what's going on first. – Ian B. Aug 31 '12 at 23:19

score 0 · Answer 2 · answered Aug 24 '12 at 11:49

0

Could you try this command?

sudo setpci -s 00:02.0 F4.b=C5

It's not persistent.

answered Aug 24 '12 at 11:49

Costales

2,278

its not working!! nothing happened and the brightness thing is still stuck! :( – Nirmik Aug 24 '12 at 19:03

score 0 · Answer 3 · answered Sep 02 '12 at 16:23

0

This is provisional solution that works for me
http://followthegeeks.com/how-to-solve-brightness-is-not-changing-issue-in-12-04/

answered Sep 02 '12 at 16:23

Mohamed

329

Brightness level issues

3 Answers3