Suspend to RAM regression retraced

Hi,

A while ago I reported a regression (http://lkml.org/lkml/2005/9/21/290)
in suspend to RAM that happened with kernel 2.6.12 on my Dell D600 laptop. After several months of testing (this is my work machine and the bug takes time to reproduce), I have finally narrowed it down. It seems like to problem was introduced between 2.6.12-rc5 and 2.6.12-rc6.

Basically, what happens is that with 2.6.12-rc6, my machine *sometimes* doesn't resume when I suspend it. This happens especially when it has been running for a while. It almost always works when I just rebooted, or if I just successfully resumed. So it behaves like "something" gets randomly corrupted, at which point the machine still works, but will not resume if I suspend it. Also, I've observed the same behaviour with and without preemption enabled.

Can someone have a look at what could cause the problem and fix it? I can provide more information if needed. BTW, I'm not on the list so please CC to me.

Thanks,

Jean-Marc

P.S. Machine setup is:
Ubuntu 5.10 (but problem also observed on 5.04 and old Debian unstable) Dell Latitude D600 (Bios rev. A14)
Pentium-M 1.6 GHz / 1 GB RAM
ATI Technologies, Inc. Radeon Mobility 9000 M9 (R250 Lf)

Thanks. You'd be best off raising a report at bugzilla.kernel.org, please.