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

Rene Herman
2007-12-07T18:46:51Z

On 07-12-07 18:19, Alan Cox wrote:

> On Fri, 7 Dec 2007 17:31:16 +0100
> Andi Kleen <andi@firstfloor.org> wrote:
>
>>> You don't need to. Port 0x80 historically is about 8uS so just udelay(8)
>>> and make sure the initial default delay is conservative enough before the
>> How would you make it conservative enough handling let's say a 6Ghz CPU
>> that can execute multiple jumps per cycle?
>
> Pick a sane worst case and go with it at boot. We don't have to be
> accurate before we tune udelay - over long in uSecs isnt going to hurt,
> and most post boot _p's can be replaced by udelay(8) now

Isn't 8 generally a bit overly long? I believe the norm is 1?

Rene.