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.
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)
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)
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!
PS how do I change the thread title to show "SOLVED"?
Last edited by jcd92 (2013-07-19 12:47:12)
Edit your first post. Tag the subject line.
Glad you got it sorted!