On Tue, Aug 14, 2012 at 7:48 PM, Ralf Baechle <ralf@xxxxxxxxxxxxxx> wrote: > On Mon, Aug 13, 2012 at 08:52:24PM +0800, Huacai Chen wrote: > >> When poweroff machine, kernel_power_off() call disable_nonboot_cpus(). >> And if we have HOTPLUG_CPU configured, disable_nonboot_cpus() is not an >> empty function but attempt to actually disable the nonboot cpus. Since >> system state is SYSTEM_POWER_OFF, play_dead() won't be called and thus >> disable_nonboot_cpus() hangs. Therefore, we make this patch to avoid >> poweroff failure. > >> diff --git a/arch/mips/kernel/process.c b/arch/mips/kernel/process.c >> index e9a5fd7..69b17a9 100644 >> --- a/arch/mips/kernel/process.c >> +++ b/arch/mips/kernel/process.c >> @@ -72,9 +72,7 @@ void __noreturn cpu_idle(void) >> } >> } >> #ifdef CONFIG_HOTPLUG_CPU >> - if (!cpu_online(cpu) && !cpu_isset(cpu, cpu_callin_map) && >> - (system_state == SYSTEM_RUNNING || >> - system_state == SYSTEM_BOOTING)) >> + if (!cpu_online(cpu) && !cpu_isset(cpu, cpu_callin_map)) > > Looks good - but I'm wondering if the "!cpu_isset(cpu, cpu_callin_map)" > can be removed as well? For X86, IA64, ARM, SPARC64 and most other arch, "!cpu_online(cpu)" is the only condition of play_dead(). I keep "!cpu_isset(cpu, cpu_callin_map)" because this does't refuse poweroff and I don't know why the old condition of play_dead() is so complex. > > Also, which -stable branches is this patch applicable? 3.3, 3.4 and 3.5 branch can use it, 3.2 and earlier kernels should do some small changes. > > Ralf >
