Arch Linux

FurryNeko

Member

Registered: 2006-10-31

Posts: 6

Bizzare Xorg & CPU Scaling Issue

Hey all,

I've stumbled upon a rather strange bug involving CPU scaling and Xorg.

I'd decided to set up CPU scaling on my desktop Athlon64 3200 as most of the time it's sat idle and any drop in heat and power would be a benefit. So I followed the guide here: http://wiki.archlinux.org/index.php/PowerNow and upon rebooting I found that there were several black 'marks' along the top of the screen once X started. See the following screenshot.

I initially blacklisted the 'cpudyn' daemon from rc.conf, rebooted and the problem went away, so I experimented further.

The black marks only ever appear if the CPU is adjusted to anything other than 'performance', which obviously explains why stopping cpudyn from loading fixes it, but if you manually set the scaling governor to anything which reduces the CPU frequency, the problem comes back.

I've tried all 3 xorg modules for my video card (GeForce 6200), vesa, nv and nvidia, the problem shows with all 3, ruling out that being a problem. I've even tried starting X as root, bypassing gnome and GDM, but still the problem persists.

Any ideas? CPU scaling isn't a necessity for me, but it'd be nice to get it working. I've searched both the forums and wiki without any luck.

Many thanks,
Neko