hibernate and suspend broken on F17 i686 desktop

[Greg Woods]

I have an i686 desktop (dual core 2GHZ Pentium 4), on which suspend and
hibernate have not worked properly since sometime in the 3.1 kernel
series. This system has 4GB RAM and uses the PAE kernel. 

Under F16, I kept updating the kernel and finding each time that suspend
and hibernate did not work, and so kept running the older kernel.
Eventually I had to move to F17. What happens with the newer kernels is,
if I suspend, the machine appears to suspend (last line on the screen is
the one about "suspending console, set no_console_suspend to debug" and
then it hangs (never powers off). Of course if I power it off manually,
the suspended image is lost and it reboots from scratch. If I hibernate
it, it does write the hibernate image to disk, prints the "suspending
console, set no_console_suspend to debug" line, and again hangs without
powering off. If I power off the machine with the power button, on
reboot it does resume properly from the hibernate image, so I think the
problem is just that it's no longer powering the machine off after
suspend/hibernate is complete. The BIOS settings have not been changed
from when it was working.

This is similar to some other threads I've seen here, but ironically, in
my case, the F17 kernels hibernate and suspend just fine on a pair of
x86_64 laptops I have (one Dell and one Sony VAIO). It's only the
desktop where they don't work.

I'm hoping, of course, that somebody will have a magic boot time kernel
parameter recipe I can try that might work, or failing that, a pointer
to some documentation on how to debug suspend/hibernate problems.

TIA,
--Greg