Arch Linux

browntown

Member

From: Salem, OR USA

Registered: 2012-11-20

Posts: 63

Acer Aspire One Intel backlight controls no worky

Hi all,  I have an aspire one whose brightness function keys always worked out of the box.  It has an intel graphics integrated.

I'm aware that kernel 3.13 changed some of the backlight issues.  It appears to have added a phantom ati card instruction set to my /sys/class/backlight/

# ls /sys/class/backlight/
acpi_video0  intel_backlight

acpi_video0 (ATI cards) never used to be there and I assume it has somehow caused some of my problems.

Is there a simple way to remove it from being there, or maybe blacklist it?

I never had to do the acpi_backlight=vendor business. But just in case, I appended  video.use_native_backlight=1 to my kernel line through grub.  Rebooted, and no change. Still 100% backlight, and no brightness button control.

Then, so I could say i tried it all, I created

/etc/X11/xorg.conf.d/20-intel.conf
Section "Device"
        Identifier  "card0"
        Driver      "intel"
        Option      "Backlight"  "intel_backlight"
        BusID       "PCI:0:2:0"

EndSection

and rebooted.

Oddly, the backlight is back at the level it was before all this mess,and i could take my sunglasses off - BUT the keys still don't work.

I'm sure all my newbishness is showing, but everything worked fine until the kernel update, now it has become an issue. 

Ideas? The !windows2012 parameter seems to only work for those that had to use the acpi_backlight=vendor before the update, so that doesn't apply.

Thank you in advance.

WonderWoofy

Member

From: Los Gatos, CA

Registered: 2012-05-19

Posts: 8,414

Re: Acer Aspire One Intel backlight controls no worky

Ideas? The !windows2012 parameter seems to only work for those that had to use the acpi_backlight=vendor before the update, so that doesn't apply.

I have a Thinkpad and the only thing that works for me is the use the acpi_osi="!Windows 2012" alone.  So I'm not sure where you got that idea.  For some people just using acpi_osi= will work as well.

browntown

Member

From: Salem, OR USA

Registered: 2012-11-20

Posts: 63

Re: Acer Aspire One Intel backlight controls no worky

[quoteSo I'm not sure where you got that idea.  For some people just using acpi_osi= will work as well.

it was from the other thread

This kernel command line parameter does nothing on my E430.  Though acpi_osi=!Windows 2012 still works just fine for me.

But since there are some here who it is working for, I have added this to the troubleshooting section of the Intel wiki page.

Nice, seems that this works just if you used

acpi_backlight=vendor

before 3.13 and it's a replace for that.

I'll try it though. and... didn't do anything.  I also tried acpi_osi=Linux, but no go.

Last edited by browntown (2014-03-03 15:20:51)

AnAkkk

Member

Registered: 2014-03-03

Posts: 148

Re: Acer Aspire One Intel backlight controls no worky

You're supposed to use video.use_native_backlight=1 on 3.13, you shouldn't mess with acpi_osi and acpi_backlight. See https://wiki.archlinux.org/index.php/backlight

If you want your problem to be fixed in the kernel for your specific laptop though, you might want to add your info to this bug report:
https://bugzilla.kernel.org/show_bug.cgi?id=35622

browntown

Member

From: Salem, OR USA

Registered: 2012-11-20

Posts: 63

Re: Acer Aspire One Intel backlight controls no worky

OK I posted in the bug tracker. I'm always worried that I'm being a super newb and finding out that the fix was in a wiki somewhere.   We will see what the kernel folks say.  I still think this is simple as blocking that acpi_video0 from generating - but I don't know the technical reasoning why it showed up in this kernel.