Arch Linux

animeshramesh

Member

Registered: 2013-03-19

Posts: 4

Full brightness. Can't configure back_light

Hi all. I know this is a redundant topic. But my problem is a bit different. <I am an Arch noob btw>

I have hybrid Intel+ATI graphics. I have their open-source drivers installed.
The brightness function keys on my laptop never worked. So I always used to echo the desired value to

/sys/class/backlight/intel_backlight/brightness

I wanted my Laptop function keys to work for modifying the brightness. When I was searching on this forum, I stumbled onto the fact that you can add acpi_osi='!Windows 2012' to grub to solve the problem. When I tried it, intel_backlight directory got deleted. And I am not able to create the same directory too.

So, I can't even echo the brightness value as I desired earlier. Any suggestions?

easysid

Member

From: India

Registered: 2013-01-01

Posts: 256

Re: Full brightness. Can't configure back_light

Please provide some info regarding you laptop.
Are there no folders under /sys/class/backlight? Try rebooting without the kernel param you added. Does the folder return?
What DE/WM are you running?
I'd suggest looking at these wiki topics (hybrid graphics are a pain)
https://wiki.archlinux.org/index.php/Hybrid_graphics
https://wiki.archlinux.org/index.php/Backlight

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Desktop screenshots :: Origami :: github

animeshramesh

Member

Registered: 2013-03-19

Posts: 4

Re: Full brightness. Can't configure back_light

Yes. Hybrid Graphics can indeed be a pain.
I had a major laptop heating problem. I did refer to
https://wiki.archlinux.org/index.php/Hybrid_graphics to minimize the temperature. Its much better now. But still, I do a have a bit of heating problems sometimes.

Now, coming back to the Brightness problem.

I am using XFCE. And yes. There are no folders in /sys/class/backlight

lspci | grep VGA
00:02.0 VGA compatible controller: Intel Corporation 2nd Generation Core Processor Family Integrated Graphics Controller (rev 09)
01:00.0 VGA compatible controller: Advanced Micro Devices [AMD] nee ATI Seymour [Radeon HD 6400M/7400M Series] (rev ff)

And thanks for replying!

easysid

Member

From: India

Registered: 2013-01-01

Posts: 256

Re: Full brightness. Can't configure back_light

Its strange that the folders did not return after removing the added kernel parameter.
What about booting with acpi_backlight=vendor as mentioned in the Backlight page?

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Desktop screenshots :: Origami :: github

animeshramesh

Member

Registered: 2013-03-19

Posts: 4

Re: Full brightness. Can't configure back_light

Still. No results.

I tried acpi_osi='Linux' too. Still, didnt work.

Last edited by animeshramesh (2013-06-24 14:15:59)

cfr

Member

From: Cymru

Registered: 2011-11-27

Posts: 7,140

Re: Full brightness. Can't configure back_light

Do you have anything under /sys/class/backlight/? If you have e.g. acpi_video0 (for example), can you control the backlight by echoing to the files in that directory?

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animeshramesh

Member

Registered: 2013-03-19

Posts: 4

Re: Full brightness. Can't configure back_light

No folders now.
I did have acpi_video0 and intel_backlight folders before. (Before I did acpi_osi='!Windows 2012')  (And only the intel_backlight used to work though)
Currently I am using redshift. But that's not the solution.