Arch Linux

eyemonen

Member

Registered: 2012-05-16

Posts: 12

Backlight problems (EliteBook 8560W)

Hi! I have HP EliteBook 8560W (i7-2630QM / Nvidia Quadro 2000M with proprietary driver) as my work laptop and recently I noticed that I can't adjust screen backlight anymore. Acpi_video0 is still there in  /sys/class/backlight but changing the value in /sys/class/backlight/acpi_video0/brightness doesn't have any effect on screen backlight which means that brightness is always set to maximum, no matter what the value is.

I have tried acpi_backlight=vendor and acpi_backlight=legacy but no luck with those. I guess it is something between kernel 3.8.8 and 3.9.2 since everything was working fine in 3.8.8 and actually downgrading kernel to 3.8.8 solves the problem.

Does anyone else have this problem? Any help would be appreciated.

WonderWoofy

Member

From: Los Gatos, CA

Registered: 2012-05-19

Posts: 8,414

Re: Backlight problems (EliteBook 8560W)

Intel graphics have been having wome wonkyness (wonkiness?) with their backlight stuff as well.  In my case, the fix is to use acpi_osi="!Windows 2012".  But I know that some have reported that using acpi_osi=Linux works for them.  Basically, what I am trying to say is that although I know pretty much nothing about Nvidia graphics on Linux (or otherwise), there are a few more acpi kernel command line options you can try.  If you use something with quotes, be sure to take note of how your particular bootloader requires that they are included in the configuration.  An example would be that grub2 has the additional options in /etc/default/grub already quoted.  So you would then need to use acpi_osi=\"!Windows 2012\".  rEFInd on the other hand indicates that you need to use double double-quotes, so acpi_osi=""!Windows 2012"".  Just be aware of what you need, as if that happens to be the option you need, but you don't quote it right, you may never know.

eyemonen

Member

Registered: 2012-05-16

Posts: 12

Re: Backlight problems (EliteBook 8560W)

Thanks WonderWoofy for information. I actually tried also acpi_osi=Linux, acpi_osi= and a couple of other combinations before posting but nothing seemed to solve the problem. Unfortunately, acpi_osi="!Windows 2012" did not work either in my case.

WonderWoofy

Member

From: Los Gatos, CA

Registered: 2012-05-19

Posts: 8,414

Re: Backlight problems (EliteBook 8560W)

Alright, well thats all I've got... so hopefully someone else can step in here who actually knows about nvidia issues (and nvidia is not without its issues).

eyemonen

Member

Registered: 2012-05-16

Posts: 12

Re: Backlight problems (EliteBook 8560W)

I have done more research about this problem and now I am even more confused. I tried a couple of old live Linux distros and could not adjust screen backlight with any of them. Got /sys/class/backlight/acpi_video0/brightness as usual but changing value didn't affect brightness at all. I'm pretty sure that it was working earlier when trying different distros. So I decided to downgrade Arch kernel (and nvidia packages) again just to see if backlight was still working with 3.8.8 and found out that it wasn't.

For me this sounds like a hardware problem. Or could it be a bios issue? Is it possible that bios has been corrupted even though everything else is still working? Logs didn't provide anything useful for me but have to say that I'm not an expert by any means with this kind of issues. Is it worthwhile to upgrade bios? This wouldn't be a big issue for me if batteries last a bit longer but they drain out pretty quickly with maximum brightness.

viliampucik

Member

Registered: 2013-06-04

Posts: 1

Re: Backlight problems (EliteBook 8560W)

I had the same issue, solved by using nvidiabl but with slightly older, 0.80 version.

dark808bb

Member

Registered: 2013-05-01

Posts: 19

Re: Backlight problems (EliteBook 8560W)

I'm also having backlight issues with my acer aspire s3.

Last edited by dark808bb (2013-06-06 18:48:18)

dark808bb

Member

Registered: 2013-05-01

Posts: 19

Re: Backlight problems (EliteBook 8560W)

I tried to echo a new value into the /sys/class/backlight/intel_backlight/brightness file but I have a permission denied error. I am using sudo and also have tried this as root with the same result.

WonderWoofy

Member

From: Los Gatos, CA

Registered: 2012-05-19

Posts: 8,414

Re: Backlight problems (EliteBook 8560W)

dark808bb, considering that your video hw is not in any way the same (yous is intel whereas this thread is about nvidia), you should probably go find a thread that fits your problem a bit better to partake in, or start your own new thread.  But there should be an intel related backlight thread (likely more), so please please search before starting something new.

cafe

Member

From: Brasil

Registered: 2014-03-20

Posts: 165

Re: Backlight problems (EliteBook 8560W)

I've posted a solution for this specific computer model here.