Re: [PATCH V2] MIPS: Fix poweroff failure when HOTPLUG_CPU configured.

On Tue, Aug 14, 2012 at 7:48 PM, Ralf Baechle [off-list ref] wrote:

On Mon, Aug 13, 2012 at 08:52:24PM +0800, Huacai Chen wrote:

quoted

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.

quoted

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?

I removed "!cpu_isset(cpu, cpu_callin_map)" and it works well on
Loongson, but I don't know whether it will affect cavium-octeon...

Also, which -stable branches is this patch applicable?

  Ralf