(sorry if I am CC'ing the wrong people, seemed for me this is related to rc-2 regression 5/6) After a very long compile sessions (is there something like git bisect to speed this up?) to find the config options that break s2ram between my minimalistic and full config I finally have some results: As soon as I enable CONFIG_TICK_ONESHOT=y CONFIG_NO_HZ=y s2ram does not anymore return from resume (just hangs). happens with git-current (i.e last commit is commit be521466feb3bb1cd89de82a2b1d080e9ebd3cb6 Author: Linus Torvalds Date: Sat Mar 10 14:22:07 2007 -0800) I am attaching a diff between the working and broken config and the working config itself. As I suspected also something broken HPET wise, I enabled CONFIG_TICK_ONESHOT=y CONFIG_HIGH_RES_TIMERS=y CONFIG_HPET_TIMER=y CONFIG_HPET_EMULATE_RTC=y CONFIG_HPET=y CONFIG_HPET_MMAP=y ( admittingly these two option too, CONFIG_X86_MCE=y CONFIG_X86_MCE_P4THERMAL=y ) and now see the same hang (config diffs attached) I then disabled the HPET stuff again and voila the kernel resumes from s2ram even with *MCE=y. Note that this can be reproduced with a minimalistic config... anyway as the intersection is CONFIG_TICK_ONESHOT I would be hoping that this is already narrowed down enough... I am not sure whether this is related, but when I boot with HPET stuff enabled it is *sometimes* necessary to put noapic as the kernel options line (else I see hangs asking me to rerun things with apic=debug) Elsewise I still see the ATA: abnormal status 0x80 on port 0x000140df ATA: abnormal status 0x80 on port 0x000140df ata1.00: configured for UDMA/33 ata3.01: revalidation failed (errno=-2) ata3: failed to recover some devices, retrying in 5 secs ATA: abnormal status 0x7F on port 0x000140df ATA: abnormal status 0x7F on port 0x000140df ata3.01: configured for UDMA/133 messages (making me shiver) directly after resume, the system is reliably functioning though... Soeren -- Sometimes, there's a moment as you're waking, when you become aware of the real world around you, but you're still dreaming.