Re: [PATCH v4 0/7] x86: BSP or CPU0 online/offline

From: Ingo Molnar
Date: Fri Dec 09 2011 - 02:30:14 EST



* Yu, Fenghua <fenghua.yu@xxxxxxxxx> wrote:

> >
> > * Fenghua Yu <fenghua.yu@xxxxxxxxx> wrote:
> > Then if demand for this picks up some more intelligent method of
> > cooperating with the firmware could be added: the firmware could
> > actually signal to us whether it supports suspend/resume from
> > other than the boot CPU.
>
> We started to think how to handle the resume issue in
> firmware, e.g. the way you talked, or change boot CPU to
> another online CPU to execute resume procedure.
>
> A firmware solution is a long run. Currently we don't
> suspend/hibernate when BSP is offline. If a firmware solution
> is available, we can change the sanity check to allow
> suspend/hibernate if CPU0 is offline for new firmware. But
> even when the solution is available in new firmware, we still
> need to do the same sanity check on legacy firmware.

Right.

You convinced me, if there's no objections i guess we could try
this feature carefully, if it's named in some more descriptive
manner such as:

x86: Arbitrary CPU hot(un)plug support

Nobody outside x86 devs knows 'BSP' means and why they should
care.

The minor usability/testability/self-test improvements i
suggested need to be added as well.

Thanks,

Ingo
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