Comment 26 for bug 34155

I don't think this bug is related to X.org's ATI driver at all.

I followed some of the suggestions above, changing /etc/default/acpi-support and editing Grub. The thing is, I tested everything in recovery mode, before X.org ~and~ the radeon kernel module are loaded. I was only able to suspend half the time. I tried removing my wireless module (ipw2200) and loading the radeon module. It all had the same effect: suspend-to-ram only resumed half of the time, regardless of the radeon module's presence. An ACPI problem, perhaps?

(I'm on a Dell C640, as well.)