Re: [PATCH] x86: provide a DMI based port 0x80 I/O delay override.

[H. Peter Anvin]

David P. Reed wrote:
> H. Peter Anvin wrote:
> > Rene Herman wrote:
> > > I do not know how universal that is, but _reading_ port 0xf0 might in 
> > > fact be sensible then? And should even work on a 386/387 pair? (I 
> > > have a 386/387 in fact, although I'd need to dig it up).
> >
> > No.  Someone might have used 0xf0 as a readonly port for other uses.
> As support: port 80 on the reporter's (my) HP dv9000z laptop clearly 
> responds to reads differently than "unused" ports.  In particular, an 
> inb takes 1/2 the elapsed time compared to a read to "known" unused port 
> 0xed - 792 tsc ticks for port 80 compared to about 1450 tsc ticks for 
> port 0xed and other unused ports (tsc at 800 MHz).

Any timings for port 0xf0 (write zero), out of curiosity?

	-hpa
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