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SubjectRe: [PATCH] x86_64: fix problems due to use of "outb" to port 80 on some AMD64x2 laptops, etc.
On Fri 2007-12-14 14:15:03, Ingo Molnar wrote:
>
> * David P. Reed <dpreed@reed.com> wrote:
>
> > Replace use of outb to "unused" diagnostic port 0x80 for time delay
> > with udelay based time delay on x86_64 architecture machines. Fix for
> > bugs 9511 and 6307 in bugzilla, plus bugs reported in
> > bugzilla.redhat.com.
> >
> > Derived from suggestion (that didn't compile) by Pavel Machek, and
> > tested, also based on measurements of typical timings of out's
> > collated by Rene Herman from many in the community.
> >
> > This patch fixes a number of bugs known to cause problems on HP
> > Pavilion dv9000z and dv6000z laptops - in the form of solid freezes
> > when hwclock is used to show or set the time. Also, it potentially
> > improves bus utilization on SMP machines, by using a waiting process
> > that doesn't tie up the ISA/LPC bus for 1 or 2 microseconds.
> >
> > i386 family fixes (completely parallel) were not included, considering
> > that such machines might involve more risk of problems on legacy
> > machines.
>
> wow, cool fix! (I remember that there were other systems as well that
> are affected by port 0x80 muckery - i thought we had removed port 0x80
> accesses long ago.)
>
> how about the simpler fix below, as a first-level approach? We can then
> remove the _p in/out sequences after this.
>
> this is also something for v2.6.24 merging.

As much as I like this patch, I do not think it is suitable for
.24. Too risky, I'd say.

--
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html


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