Can't change brightness Ubuntu 13

**Heinzelmannchen** · May 29th, 2013

I recently updated to ubuntu 13.04 and needed to change the brightness because i was getting a blank screen on login. FN+UP temporarily fixed this.

i entered the following in /etc/default/grub

Code:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=linux acpi_backlight=vendor"

and that fixed the blank screen problem but now i can change the brightness. how can i make it so i can change the brightness settings again?

**Toz** · May 29th, 2013

What is the make/model of your computer and what video card(s) and drivers do you have? This might help:

Code:

sudo lspci -vnn | grep -A12 VGA

(Stab in the dark) You might want to try:

Code:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=\"!Windows 2012\""

...instead of "acpi_osi=linux acpi_backlight=vendor". It seems to be a valid workaround for newer devices. As a reminder, make sure you run "sudo update-grub" afterwards to commit the change to grub.

**Heinzelmannchen** · May 29th, 2013

Originally Posted by Toz

What is the make/model of your computer and what video card(s) and drivers do you have? This might help:

Code:

sudo lspci -vnn | grep -A12 VGA

(Stab in the dark) You might want to try:

Code:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=\"!Windows 2012\""

...instead of "acpi_osi=linux acpi_backlight=vendor". It seems to be a valid workaround for newer devices. As a reminder, make sure you run "sudo update-grub" afterwards to commit the change to grub.

Sorry about that. I have lenovo g580

here is

Code:

sudo lspci -vnn | grep -A12 VGA

00:02.0 VGA compatible controller [0300]: Intel Corporation 3rd Gen Core processor Graphics Controller [8086:0166] (rev 09) (prog-if 00 [VGA controller])
Subsystem: Lenovo Device [17aa:3977]
Flags: bus master, fast devsel, latency 0, IRQ 44
Memory at e0000000 (64-bit, non-prefetchable) [size=4M]
Memory at d0000000 (64-bit, prefetchable) [size=256M]
I/O ports at 3000 [size=64]
Expansion ROM at <unassigned> [disabled]
Capabilities: [90] MSI: Enable+ Count=1/1 Maskable- 64bit-
Capabilities: [d0] Power Management version 2
Capabilities: [a4] PCI Advanced Features
Kernel driver in use: i915

00:14.0 USB controller [0c03]: Intel Corporation 7 Series/C210 Series Chipset Family USB xHCI Host Controller [8086:1e31] (rev 04) (prog-if 30 [XHCI])

**Toz** · May 29th, 2013

Did you try the acpi_osi=\"!Windows 2012\" kernel boot parameter?

**Heinzelmannchen** · May 29th, 2013

Yes i tried entering that then updated grub. After restarting i'm still not able to change brightness.

**Toz** · May 30th, 2013

Can you post back the results of:

Code:

cat /proc/cmdline

...after booting with the acpi_osi=\"!Windows 2012\" kernel boot parameter?

Also, can you post back the contents of your dmesg log file like this:

Code:

pastebinit /var/log/dmesg

...and post back the link that is generated.

You might also want to try each of the existing ones separately:

Code:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=Linux"

Code:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_backlight=vendor"

**Heinzelmannchen** · May 30th, 2013

Code:

cat /proc/cmdline

BOOT_IMAGE=/boot/vmlinuz-3.8.0-22-generic root=UUID=37d6764d-d42f-4b4b-a693-7579383559fb ro quiet splash acpi_osi=linux acpi_backlight=vendor vt.handoff=7

Pastebin

**Heinzelmannchen** · May 30th, 2013

The following works

Code:

GRUB_CMDLINE_LINUX_DEFAULT="quiet splash acpi_osi=Linux"

Thanks for the support. I always feel so dumb when i can't figure this stuff out on my own.
I couldn't find much on the subject when searching, maybe i didn't look hard enough. Oh well i really appreciate your help =).

**arthurborsboom2** · October 22nd, 2013

I confirm that on a Acer Aspire V5-171 (Intel 3rd generation i915), the above statement got the brightness controls working again.

Ubuntu 13.10 x64
Kernel: 3.11.6