4

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.)

ish
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Nirmik
  • 7,938

3 Answers3

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?

Community
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Ian B.
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0

Could you try this command?

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

It's not persistent.

Costales
  • 2,318
0

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

Mohamed
  • 329