Shutdown problem in SMP system happened on Tegra20

[linux@arm.linux.org.uk (Russell King - ARM Linux)]

On Sat, Aug 25, 2012 at 08:00:56AM +0800, Bill Huang wrote:
> nvpublic
> > So what you're asking for is a feature to do what CONFIG_PM_SLEEP_SMP does, but without
> > CONFIG_PM_SLEEP_SMP enabled?
> 
> Yeah pretty much, I'm actually asking should we take care of this since maybe not all platforms 
> will have this config enabled?
> > 
> > Why not just ensure that CONFIG_PM_SLEEP_SMP is enabled if your platform requires that the lowest CPU
> > number be the CPU dealing with reboot?
> 
> Someday we will have it enabled, but before that we'll hit the issue, so you don't think
> this should be taken care of? Thanks.

Well, just enable CONFIG_PM_SLEEP_SMP then - it'll be far better than
trying to implement something in the ARM code, especially as sysrq can
be used for poweroff/reboot etc (which will run from atomic contexts
where you can't switch to another CPU.)

What you're asking for will make these callbacks fragile for other
platforms.