Messages in this thread Patch in this message | | | Date | Fri, 28 Sep 2007 09:22:34 -0400 | From | Mark Lord <> | Subject | Re: Problems with SMP & ACPI powering off |
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Rafael J. Wysocki wrote: > On Friday, 28 September 2007 06:57, Len Brown wrote: >> On Thursday 27 September 2007 18:00, Rafael J. Wysocki wrote: >>> On Thursday, 27 September 2007 23:29, Mark Lord wrote: >>>> Question: do we disable all CPUs except 0 when doing ACPI power off? >>> No, but we should. >> We used to. >> It is absolutely mandatory -- else it confuses the BIOS on some boards >> b/c it isn't expecting SMM to get entered from other than cpu0. > > Can we use the CPU hotplug for that, like in the suspend/hibernation case?
Well, so far it's working: about ten poweroffs since I patched it, and no issues with any of them. Prior to that, it seemed like about one in five poweroffs wouldn't (power off).
It'll take a lot more testing to confirm, though.
What can I call to determine if more than one CPU is enabled, anyway?
Here's the hack I'm using here, very situation (2 cores) specific, and it still has some printk's leftover with a sleep so I have time to read them before the lights go out. :)
--- old/arch/i386/kernel/reboot.c 2007-09-27 17:17:00.000000000 -0400 +++ linux/arch/i386/kernel/reboot.c 2007-09-27 17:15:35.000000000 -0400 @@ -393,8 +393,22 @@ .halt = native_machine_halt, }; +static void kill_cpu1(void) +{ + extern int cpu_down(unsigned int cpu); + + printk(KERN_EMERG "kill_cpu1: was running on CPU%d\n", smp_processor_id()); + /* Some bioses don't like being called from CPU != 0 */ + set_cpus_allowed(current, cpumask_of_cpu(0)); + printk(KERN_EMERG "kill_cpu1: now running on CPU%d\n", smp_processor_id()); + cpu_down(1); + printk(KERN_EMERG "kill_cpu1: done\n"); + msleep(1000); +} + void machine_power_off(void) { + (void)kill_cpu1(); machine_ops.power_off(); } - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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