Date: Thu, 19 Sep 1996 07:29:39 +0200 (MET DST) From: hm@kts.org (Hellmuth Michaelis) To: dg@root.com Cc: durian@plutotech.com, msmith@atrad.adelaide.edu.au, freebsd-hackers@FreeBSD.org Subject: Re: Special Cycles on the PCI bus Message-ID: <m0v3bgB-00000bC@ernie.kts.org> In-Reply-To: <199609181626.JAA12461@root.com> from "David Greenman" at Sep 18, 96 09:26:50 am
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David Greenman wrote:
> Perhaps they are caused by the inb(0x84)'s that are used as time delays in
> a couple places of the kernel. The inb(0x84) is supposed to be an unused port
> and thus should take about 1.25us to read from. This isn't always true,
> however, as people have pointed out in the past. We should probably replace
> the last few places where these are used with a calibrated wait loop.
And then the old question appears again - how to do (relatively) precise
delays in the range of 1 us ... 10 us. As far as i understood Bruce that
time, DELAY isn't able to handle this precisely. Has that changed ?
hellmuth
--
Hellmuth Michaelis hm@kts.org Hamburg, Europe
(A)bort, (R)etry, (I)nstall BSD ?
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