Arch Linux

blah1898

Member

Registered: 2013-04-22

Posts: 14

Backlight keys issue on Asus G75VW

I just installed Arch Linux with Gnome and the nvidiabl driver from https://github.com/guillaumezin/nvidiabl , and it seems to work. If I do "echo x > /sys/class/backlight/nvidia_backlight/brightness" the brightness does change. However, if I try to use my shortcut keys (Fn+F5, Fn+F6), the brightness does not change. It seems that Gnome edits "/sys/class/backlight/acpi_video0/brightness", which obviously doesn't change my screen brightness. I've tried the following:

- Adding "acpi_osi=Linux acpi_backlight=vendor" to my boot settings: Gnome doesn't even react to my Fn+F4 Fn+F5 keys.
- Loading nvidiabl with the option "type=firmware": nothing changes.

I couldn't find any help on the internet concerning this issue, so any help would be appreciated.

WonderWoofy

Member

From: Los Gatos, CA

Registered: 2012-05-19

Posts: 8,414

Re: Backlight keys issue on Asus G75VW

The Intel GPUs had some craziness with backlight stuff very recently.  What seems to fix it is not telling acpi that it is Linux but rather that it is not windows.  So I have this in my gummiboot configurations:

options <bunch of kernel command line stuff> acpi_osi="!Windows 2012" 

The tricky part is figuring out how to use double quotes with the kernel command line in your bootloader's config.  Gummiboot was simple, as it has no double wuotes around the options in the first place.  But grub for example, does use double quotes, so I think you have to escape the double quotes around the windows stuff above.  I use elilo as a backup, and escaping the quotes there work as well.  Refind documentation is the only i have found that actually addresses this and instructs to double double quote (acpi_osi=""!Windows 2012"").

Whether or not this will fix your nvidia issue, I have no idea, as I don't use an nvidia card in any of my machines.

Good luck!

hadrons123

Member

From: chennai

Registered: 2011-10-07

Posts: 1,249

Re: Backlight keys issue on Asus G75VW

ACPI guys have to fix the LVDS black screen issue. Currently most of us with intel ivybridge are using kernel command paramaters to circumvent the issue. You can file a bug in linux kernel at https://bugzilla.kernel.org/.

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LENOVO Y 580 IVYBRIDGE 660M NVIDIA
Unix is user-friendly. It just isn't promiscuous about which users it's friendly with. - Steven King

blah1898

Member

Registered: 2013-04-22

Posts: 14

Re: Backlight keys issue on Asus G75VW

Hey, just a quick update, it seems that WonderWoofy's suggestion did nothing. but anyways, I can live with having to type "echo 10 > /sys/class/backlight/nvidia_backlight/brightess" to prevent the screenfrom burning my eyes . However, I hope they fix this sooner or later.