From owner-freebsd-arch  Thu Jan  3 14:48:50 2002
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Date: Fri, 4 Jan 2002 09:49:03 +1100 (EST)
From: Bruce Evans <bde@zeta.org.au>
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To: Poul-Henning Kamp <phk@critter.freebsd.dk>
Cc: Mike Silbersack <silby@silby.com>, <freebsd-arch@FreeBSD.ORG>
Subject: Re: DELAY accuracy Re: cvs commit: src/sys/dev/usb uhci.c 
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On Thu, 3 Jan 2002, Poul-Henning Kamp wrote:

> If we look at DELAY(1), which is a very common value, considering
> the typical use, I suspect it may actually be specified not for the
> delay as much for various "things to happen", things which might be
> better provoked by memory barriers or similar.
>
> Either way, in i386 I think DELAY(1) would be best implemented as
> 	inb(0x80)

This mistake has been made before.  inb(0x80) is too fast on some machines.

Bruce


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