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SubjectRe: [ACPI] Re: Linux 2.4.26-rc1 (cmpxchg vs 80386 build)
On Wed, 31 Mar 2004, Jamie Lokier wrote:

> > Well, "cmpxchg", "xadd", etc. can be easily emulated with an aid of a
> > spinlock. With SMP operation included.
>
> Nope. Len Brown wrote:
>
> > Linux uses this locking mechanism to coordinate shared access
> > to hardware registers with embedded controllers,
> > which is true also on uniprocessors too.
>
> You can't do that with a spinlock. The embedded controllers would
> need to know about the spinlock.

Hmm, does it mean we support x86 systems where an iomem resource has to
be atomically accessible by a CPU and a peripheral controller?

--
+ Maciej W. Rozycki, Technical University of Gdansk, Poland +
+--------------------------------------------------------------+
+ e-mail: macro@ds2.pg.gda.pl, PGP key available +
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