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

Rene Herman
2007-12-11T06:56:19Z

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.