Re: [PATCH] x86_64: fix problems due to use of "outb" to port 80on some AMD64x2 laptops, etc.

[Pavel Machek]

On Fri 2007-12-14 18:36:26, Alan Cox wrote:
> > > i dont think this should matter: old systems that truly _need_ the ISA 
> > > delay will be slow enough to not trip up. (nor are they really affected 
> > > by these early delays - the delays were more for crappy ISA devices that 
> > > get initialized later down, when the delay loop is already calibrated)
> > 
> > 8253 (DMAC) and 8254 (PIT) have been reported in earlier versions of the 
> > thread. By Alan, I believe.
> 
> They've been seen to be problems up to PII era machines. I'm not aware of
> any newer than that with this problem. We also don't need to touch the
> DMAC that early anyway that I can see - just the PIT.
> 
> In fact if we have a fast processor we have a TSC and APIC so we don't
> need the PIT ?

It is still good to be able to disable APIC/TSC. Neither are
particulary reliable time sources.

-- 
(english) http://www.livejournal.com/~pavelmachek
(cesky, pictures) http://atrey.karlin.mff.cuni.cz/~pavel/picture/horses/blog.html
--
To unsubscribe from this list: send the line "unsubscribe linux-kernel" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at  http://vger.kernel.org/majordomo-info.html
Please read the FAQ at  http://www.tux.org/lkml/