Date: Thu, 3 Jan 2002 18:16:41 -0500 (EST) From: Mike Silbersack <silby@silby.com> To: Poul-Henning Kamp <phk@critter.freebsd.dk> Cc: Bruce Evans <bde@zeta.org.au>, <freebsd-arch@FreeBSD.ORG> Subject: Re: DELAY accuracy Re: cvs commit: src/sys/dev/usb uhci.c Message-ID: <Pine.BSF.4.30.0201031809360.45843-100000@niwun.pair.com> In-Reply-To: <2971.1010094530@critter.freebsd.dk>
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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. Sound about right. Few of the calls using multiples of ten explained why they were sleeping for the appropriate amount of time. Those with explicit purpose seems to state so (and are not multiples of ten.) > Either way, in i386 I think DELAY(1) would be best implemented as > inb(0x80) Maybe a new call could be added instead? waitforpipelineswritebackspcibuffersandstufftoclear() sounds good. > Arguments for DELAY of 1msec and higher should be converted to > tsleep() + HZ=1000. Sounds like a good junior kernel hacker task. Mike "Silby" Silbersack To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-arch" in the body of the message
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