petecb via coreboot wrote:
Narrow the problem down by booting any common Linux distribution (the install media is fine) and as root suspending with
echo mem > /sys/power/state
..and see if resume works there. If yes coreboot is not neccessarily off the hook, but xen/Qubes is at least involved.
Thanks for this suggestion. I have now tried it with a Fedora and a Knoppix live CD and neither of them can resume from suspend.
Those are good data points!
They indicate a coreboot problem; ie. not at all related to xen/Qubes.
Now it would be very helpful to get debug output from coreboot, which requires specific hardware. With luck you can use a USB->serial-adapter that you already have (only specific ones work), otherwise you'll need e.g. a BeagleBone Black to function as a USB Debug Device.
Or if you are really lucky :) the KGPE-D16 already has a serial port and you just have to rebuild coreboot with debugging enabled.
//Peter