Date: Wed, 10 Apr 2002 14:27:06 -0400 (EDT) From: John Baldwin <jhb@FreeBSD.org> To: Jake Burkholder <jake@locore.ca> Cc: Brian Somers <brian@FreeBSD.org>, cvs-committers@FreeBSD.org, cvs-all@FreeBSD.org, Bruce Evans <bde@zeta.org.au> Subject: Re: cvs commit: src/sys/dev/digi digi.c Message-ID: <XFMail.20020410142706.jhb@FreeBSD.org> In-Reply-To: <20020410105203.B209@locore.ca>
next in thread | previous in thread | raw e-mail | index | archive | help
On 10-Apr-2002 Jake Burkholder wrote: > Apparently, On Wed, Apr 10, 2002 at 09:06:18AM -0400, > John Baldwin said words to the effect of; > >> >> On 10-Apr-2002 Bruce Evans wrote: >> > On Tue, 9 Apr 2002, Brian Somers wrote: >> > >> >> brian 2002/04/09 20:13:28 PDT >> >> >> >> Modified files: >> >> sys/dev/digi digi.c >> >> Log: >> >> Add a digi_delay() function and use it instead of tsleep() when polling >> >> the card for command completion. >> >> >> >> digi_delay() uses either tsleep() or DELAY() depending on the value of >> >> ``cold''. >> >> >> >> Pointed in the right direction by: jhb >> > >> > Maybe tsleep() should sleep when cold if given a timeout. This is not >> > quite >> > right, since the semantics of the timeout arg is to give a maximum wait, >> > not a delay, but it is better than ... >> > >> >> >> >> Revision Changes Path >> >> 1.25 +14 -5 src/sys/dev/digi/digi.c >> > >> > N * (+14 -5) in N drivers. All drivers that support dynamic loading need >> > something like this, since busy-waiting on running systems is >> > unacceptable. >> > Not that I will ever want to use this misfeature. >> >> I've thought about having some sort of separate API for code that just ways >> to >> delay. Right now they use tsleep() on a channel that never gets woken up >> with >> a timeout. If we had a delay(int timo) function then it could use a callout >> when callouts were working and fall back to DELAY() in the cold case. > > No, this is wrong. Anything that uses cold is wrong. The correct fix is to > move the clock initialization earlier in boot to be before the device probe. I wouldn't object to doing that but that isn't trivial. I also have a pet peeve about (ab)using tsleep() to do delays but that is a more minor issue. > Jake -- John Baldwin <jhb@FreeBSD.org> <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve!" - http://www.FreeBSD.org/ To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe cvs-all" in the body of the message
Want to link to this message? Use this URL: <https://mail-archive.FreeBSD.org/cgi/mid.cgi?XFMail.20020410142706.jhb>