@kernellogger That's it! My laptop has just survived 10 suspend-resume cycles on battery power with autosuspend off, but it hanged on the first attempt on AC power with autosuspend enabled.
Is it too cynical to expect that (some) distributions would fix the issue by adding the following command to their suspend hook?
echo on > /sys/bus/scsi/devices/0:0:0:0/power/control