Arch Linux

comapony

Member

Registered: 2014-01-18

Posts: 24

[SOLVED] laptops backlight not powering on after suspend

I'm on the g+ arch community, it seems that a few of us there have an issue with our laptops not waking from suspend, and I've seen a few issues like this, here, on the arch forum.

http://pastebin.com/eXebMFTy

This is my dmesg after the said issue occurs...
I'm on an intel macbook 4,1 with kernel 3.15.1-1-ARCH.

I looked at the arch wiki page about backlights, and it said that I could get info on my backlight drivers at /sys/class/backlight. I'm guessing that since using intel graphics drivers, I should have a directory there called intel-backlight, or intel-dri, or something, but it's empty. This doesn't seem kosher... and it seems that a lot of us on the g+ community are using intel drivers, and this started happening for me after/around-the-same-time-as I did a pacman -Syu that upgraded my intel-dri and xf86-video-intel.

Last edited by comapony (2014-07-15 22:55:31)

Rexilion

Member

Registered: 2013-12-23

Posts: 784

Re: [SOLVED] laptops backlight not powering on after suspend

Did this ever work on another kernel version? Perhaps also post a dmesg of a working situation, if possible.

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R00KIE

Forum Fellow

From: Between a computer and a chair

Registered: 2008-09-14

Posts: 4,734

Re: [SOLVED] laptops backlight not powering on after suspend

You first have to determine if the machine really doesn't wake up or if it wakes up but you don't see anything on the screen.

If possible you should try to ssh into your computer from another machine and see if it works. Alternatively you could try to suspend from a vt or terminal and try to restart the machine from there. If restarting the machine works then you know it wakes up but you don't see anything on the screen, otherwise it might be hanging when waking up.

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R00KIE
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comapony

Member

Registered: 2014-01-18

Posts: 24

Re: [SOLVED] laptops backlight not powering on after suspend

You first have to determine if the machine really doesn't wake up or if it wakes up but you don't see anything on the screen.

Sorry, I should've mentioned that, yes, it's just the backlight. If I take a flashlight the to the screen, I can see stuff there, and I can see stuff changing if I were to start scrolling, mashing buttons, et cetera. I can ssh to the machine in question and restart it, I also tried 'xset dpms force on' over ssh, but it fails because it says the display isn't recognized, even if I set DISPLAY manually. Before a suspend, I'm able to 'xset force dpms off && sleep 5 && xset force dpms on' successfully.

Did this ever work on another kernel version?

I upgraded to 3.15.2-1-ARCH last night, it didn't have any effect. I'll try a downgrade tonight, and I'll check my pacman.log to see if I had a kernel upgrade around-the-same-time-as the backlight started fucking up.

comapony

Member

Registered: 2014-01-18

Posts: 24

Re: [SOLVED] laptops backlight not powering on after suspend

In case anyone still cares, the issue was resolved by downgrading the kernel to 3.14.6-1. Now that 3.15.5-1 is out, I'm no longer experiencing issues with the backlight refusing to come on after suspends.