On Saturday, 28 July 2007 18:55, Linus Torvalds wrote: > > On Sat, 28 Jul 2007, Linus Torvalds wrote: > > > > And it's the *top*level* code that selects HOTPLUG_CPU. Through > > SUSPEND_SMP (which will select HOTPLUG_CPU) and SOFTWARE_SUSPEND. > > In other words, the problem seems to be that > > kernel/power/main.c: > suspend_devices_and_enter() > > does the proper "disable/enable_nonboot_cpus()", but it does so without > having enabled CPU hotplug. > > And you seem to think that it's ACPI that should enable the hotplug, even > though the code that actually needs it is _outside_ ACPI. And I think > that's wrong, and that this is a bug. > > So I think the real issue is that we allow that > "suspend_devices_and_enter()" code to be compiled without HOTPLUG_CPU in > the first place. It's not supposed to work that way. > > Of course, it may well be that other architectures can happily suspend > even with multiple CPU's active, which may be the cause of this mess. But > I really think it shouldn't be ACPI that has to select the CPU hotplug, > since it's not ACPI that _uses_ it in the first place. > > Rafael: making a config option for STR (the same way we have a config > option for hibernate), and just not allowing it on SMP without HOTPLUG_CPU > seems to be the right thing. Len is right in that we do insane things > right now (trying to STR with multiple CPU's still active), and I just > don't think he's the one that should work around it! Well, I agree and that's why I asked. :-) OK, I'll prepare a patch to introduce CONFIG_SUSPEND, but that will require quite a bit of (compilation) testing on different architectures. Greetings, Rafael -- "Premature optimization is the root of all evil." - Donald Knuth - To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
