From: Jamie Lokier <lk@tantalophile.demon.co.uk>
To: Mark Hahn <hahn@coffee.psychology.mcmaster.ca>
Cc: linux-kernel@vger.kernel.org
Subject: Re: Linux Post codes during runtime, possibly OT
Date: Fri, 26 Jan 2001 16:31:03 +0100 [thread overview]
Message-ID: <20010126163103.F7096@pcep-jamie.cern.ch> (raw)
In-Reply-To: <Pine.LNX.3.95.1010126095653.762A-100000@chaos.analogic.com> <Pine.LNX.4.10.10101261012010.18973-100000@coffee.psychology.mcmaster.ca>
In-Reply-To: <Pine.LNX.4.10.10101261012010.18973-100000@coffee.psychology.mcmaster.ca>; from hahn@coffee.psychology.mcmaster.ca on Fri, Jan 26, 2001 at 10:15:02AM -0500
Mark Hahn wrote:
> > #ifdef SLOW_IO_BY_JUMPING
> > #define __SLOW_DOWN_IO "\njmp 1f\n1:\tjmp 1f\n1:"
> > #else
> > -#define __SLOW_DOWN_IO "\noutb %%al,$0x80"
> > +#define __SLOW_DOWN_IO "\noutb %%al,$0x19"
>
> this is nutty: why can't udelay be used here? empirical measurements
> in the thread show the delay is O(2us).
Does anyone remember where __SLOW_DOWN_IO is needed any more?
udelay() makes sense. Modern drivers use small udelays themselves to
confirm to chip specs.
Some ISA drivers appear to use outb_p "just to be on the safe side", no
idea if it's appropriate or not. Some even mix outb and outb_p based on
educated guesses. I know, I've written such code :-)
-- Jamie
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next prev parent reply other threads:[~2001-01-26 15:31 UTC|newest]
Thread overview: 39+ messages / expand[flat|nested] mbox.gz Atom feed top
2001-01-26 15:41 Petr Vandrovec
2001-01-26 15:07 ` Richard B. Johnson
2001-01-26 15:15 ` Mark Hahn
2001-01-26 15:31 ` Jamie Lokier [this message]
2001-01-26 16:03 ` Richard B. Johnson
2001-01-26 16:22 ` Jamie Lokier
-- strict thread matches above, loose matches on Subject: below --
2001-01-26 15:42 Manfred Spraul
2001-01-26 16:07 ` Richard B. Johnson
2001-01-26 16:33 ` Brian Gerst
2001-01-27 12:28 ` Pavel Machek
2001-01-25 21:46 Ian S. Nelson
2001-01-25 22:26 ` H. Peter Anvin
2001-01-25 22:31 ` Matthew Dharm
2001-01-25 22:32 ` H. Peter Anvin
2001-01-25 22:41 ` Matthew Dharm
2001-01-25 22:45 ` H. Peter Anvin
2001-01-25 23:08 ` Richard B. Johnson
2001-01-25 23:10 ` H. Peter Anvin
2001-01-26 13:58 ` Richard B. Johnson
2001-01-26 16:19 ` H. Peter Anvin
2001-01-26 17:54 ` David Welch
2001-01-29 2:35 ` Paul Gortmaker
2001-01-27 10:20 ` Rogier Wolff
2001-01-27 20:47 ` H. Peter Anvin
2001-01-27 21:01 ` Rogier Wolff
2001-01-27 21:24 ` H. Peter Anvin
2001-01-28 10:12 ` Rogier Wolff
2001-01-28 10:18 ` H. Peter Anvin
2001-01-28 11:03 ` Rogier Wolff
2001-01-28 17:22 ` Jamie Lokier
2001-01-28 22:34 ` Pavel Machek
2001-01-29 15:09 ` Richard B. Johnson
2001-01-29 19:21 ` H. Peter Anvin
2001-01-28 22:29 ` Pavel Machek
2001-01-30 17:44 ` Mark H. Wood
2001-01-30 18:10 ` Richard B. Johnson
2001-01-30 18:16 ` mirabilos
2001-01-30 18:36 ` Richard B. Johnson
2001-01-30 18:41 ` mirabilos
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