Re: RFC: outb 0x80 in inb_p, outb_p harmful on some modern AMD64 with MCP51 laptops

[Rene Herman <rene.herman@keyaccess.nl>]

On 11-12-07 02:25, H. Peter Anvin wrote:

> David Newall wrote:
> > Where did the 8us delay come from?  The documentation and source is 
> > careful not to say how long the delay is.  Would changing it to, say 
> > 1us, be technically wrong?  Is code that requires 8us correct?
>
> I think a single ISA bus transaction is 1 µs, so two of them back to 
> back should be 2 µs, not 8 µs...

Sigh. And now where do these _two_ transactions come from? (and yes, see 
Alan's folowups, a transaction on a spec bus is 1 us).

Rene.
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