Re: [ACPI] Re: Linux 2.4.26-rc1 (cmpxchg vs 80386 build)

[Maciej W. Rozycki]

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@xxxxxxxxxxxxx, PGP key available        +
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