From owner-freebsd-current Thu Dec 2 14:13:41 1999 Delivered-To: freebsd-current@freebsd.org Received: from mass.cdrom.com (mass.cdrom.com [204.216.28.184]) by hub.freebsd.org (Postfix) with ESMTP id 152A314F24; Thu, 2 Dec 1999 14:13:37 -0800 (PST) (envelope-from msmith@mass.cdrom.com) Received: from mass.cdrom.com (localhost [127.0.0.1]) by mass.cdrom.com (8.9.3/8.9.3) with ESMTP id OAA00629; Thu, 2 Dec 1999 14:06:58 -0800 (PST) (envelope-from msmith@mass.cdrom.com) Message-Id: <199912022206.OAA00629@mass.cdrom.com> X-Mailer: exmh version 2.1.1 10/15/1999 To: Warner Losh Cc: "Matthew N. Dodd" , Nick Hibma , Christopher Masto , Mike Smith , FreeBSD CURRENT Mailing List Subject: Re: PCCARD eject freeze (was Re: your mail) In-reply-to: Your message of "Thu, 02 Dec 1999 12:11:51 MST." <199912021911.MAA03854@harmony.village.org> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Date: Thu, 02 Dec 1999 14:06:58 -0800 From: Mike Smith Sender: owner-freebsd-current@FreeBSD.ORG Precedence: bulk X-Loop: FreeBSD.ORG > In message "Matthew N. Dodd" writes: > : On Thu, 2 Dec 1999, Nick Hibma wrote: > : > PCMCIA has the problem that the hardware register you are talking to can > : > disappear on the spot, between 2 outb()s. > : > : Can't we do something about this using bus_space? This would give us a > : fair bit of overhead for PCMCIA devices as well as require us to more > : tightly couple newbus and bus_space (we'd probably want to 'cache' a > : function pointer to the method to avoid method lookup overhead.) > > I had the same thought, but w/o a signal or other out of band error > communication, I'm not sure how to implement this. You can't without a race. You'd have to poll the hardware before and after every I/O operation to ensure that it was still there. Yick. -- \\ Give a man a fish, and you feed him for a day. \\ Mike Smith \\ Tell him he should learn how to fish himself, \\ msmith@freebsd.org \\ and he'll hate you for a lifetime. \\ msmith@cdrom.com To Unsubscribe: send mail to majordomo@FreeBSD.org with "unsubscribe freebsd-current" in the body of the message