On Mon, 2007-03-05 at 09:14 +0100, Ingo Molnar wrote: > * Soeren Sonnenburg wrote: > > > a rather long git bisect session between v2.6.20 and HEAD identified > > the commit below this as the cause. please note that the machine does > > not return from resume and although all PM debug was turned on there > > is nothing in the logs. happens with a minimalistic setup (console > > only no audio/network etc) without SMP and CONFIG_HPET_TIMER but > > PREEMPT on > > good. Could you apply the patch below, enable CONFIG_PM_DEBUG and > CONFIG_PM_TRACE and CONFIG_DISABLE_CONSOLE_SUSPEND, boot into the new > kernel and do: > > echo 1 > /proc/sys/kernel/acpi_simulate_suspend_to_ram > echo mem > /sys/power/state > > and if the system still works after this point, could you send us the > resulting dmesg? Or if it crashes, hopefully the crash should be right > on the screen - how does it look like? I did the following: applied your patch (with the fix that I moved the acpi_simulate_suspend_to_ram = 1 initialization to the sleep/main.c file, else compilation fails; I guess that if this should go into the mainline kernel it should be = 0). I then tested whether the kernel still works before e9e2cdb412412326c4827fc78ba27f410d837e6e with acpi_simulate_suspend_to_ram_drivers = 0 and = 1. worked. I then did git cherry-pick e9e2cdb412412326c4827fc78ba27f410d837e6e and same procedure: acpi_... = 0 -> freeze on resume acpi_... = 1 lead to the attached dmesg output. no crash whatsoever. Please note that even with CONFIG_DISABLE_CONSOLE_SUSPEND enabled (and acpi_simulate_suspend_to_ram_drivers = 0) the display turns off and fails to turn back on (though the machine is still alive after resume as another s2ram cycle/typeing reboot on the cmdline proves; this can be fixed using certain s2ram option which however vary between kernel versions, wrong ones cause again a hang on resume. s2ram -f -p or s2ram -f -m). 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.