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#1 2013-07-14 19:06:25

jcd92
Member
Registered: 2013-06-04
Posts: 6

[SOLVED] Any known issues with backlight not turning off in suspend?

Hi All,
I've got a slightly old image of Arch (March 2013, using X 1.13 due to a problem with r128 video driver) running on a Dell C600.  The only problem is that when I suspend or even hibernate, the LCD backlight stays on!  Is this a known issue?  I'd like to avoid updating to the latest unless I know this is something that was solved, given the r128 driver issue with X 1.14

The graphics card is an ATI Rage Mobility 128.   The problem still occurs if I use the vesa driver.

Cheers
Jon

Solution: pm-utils turns off the backlight BUT you need to bypass the systemd.logind handler first, as it doesn't work, and you end up double-suspending.

Last edited by jcd92 (2013-07-22 15:28:44)

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#2 2013-07-15 01:16:46

cfr
Member
From: Cymru
Registered: 2011-11-27
Posts: 5,663

Re: [SOLVED] Any known issues with backlight not turning off in suspend?

I'm not sure what you mean by an "image of Arch"? Do you mean that you are booting the .iso image? That is, Arch isn't installed to disk?

What is in /sys/class/backlight/?

How do you suspend or hibernate the machine?

Last edited by cfr (2013-07-15 01:17:09)


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#3 2013-07-19 12:44:51

jcd92
Member
Registered: 2013-06-04
Posts: 6

Re: [SOLVED] Any known issues with backlight not turning off in suspend?

I found the issue.  I assumed the power management lid switch response was being handled by acpid, but first it was being picked up by systemd.logind, which doesn't have any of the special tricks needed for this GPU.  Then I was getting a double-suspend because after opening the lid, the apcid handler was kicking in from the previous close, and interestingly it *was* turning off the backlight.

So, I've disabled the systemd.login handling of the lid switch by setting it to ignore, and using acpid's handler.sh to call
pm-utils suspend --quirk-radeon-off.

It all works beautifully now!  Hoorah!

Jon

PS how do I change the thread title to show "SOLVED"?

Last edited by jcd92 (2013-07-19 12:47:12)

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#4 2013-07-19 21:37:37

cfr
Member
From: Cymru
Registered: 2011-11-27
Posts: 5,663

Re: [SOLVED] Any known issues with backlight not turning off in suspend?

Edit your first post. Tag the subject line.

Glad you got it sorted!


How To Ask Questions The Smart Way | Help Vampires

Arch Linux | x86_64 | GPT | EFI boot | grub2 | systemd | LVM2 on LUKS
Lenovo x121e | Intel(R) Core(TM) i3-2367M CPU @ 1.40GHz GenuineIntel | Intel Centrino Wireless-N 1000 | US keyboard with Euro | 320G 7200 RPM Seagate HDD

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#5 2013-07-22 15:29:07

jcd92
Member
Registered: 2013-06-04
Posts: 6

Re: [SOLVED] Any known issues with backlight not turning off in suspend?

Splendid!  Thanks!

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