From owner-freebsd-hackers@FreeBSD.ORG Wed Oct 26 17:23:34 2005 Return-Path: X-Original-To: freebsd-hackers@freebsd.org Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id E31C516A422 for ; Wed, 26 Oct 2005 17:23:34 +0000 (GMT) (envelope-from jhb@freebsd.org) Received: from mv.twc.weather.com (mv.twc.weather.com [65.212.71.225]) by mx1.FreeBSD.org (Postfix) with ESMTP id 7E73343D46 for ; Wed, 26 Oct 2005 17:23:34 +0000 (GMT) (envelope-from jhb@freebsd.org) Received: from [10.50.41.234] (Not Verified[10.50.41.234]) by mv.twc.weather.com with NetIQ MailMarshal (v6, 0, 3, 8) id ; Wed, 26 Oct 2005 13:39:37 -0400 From: John Baldwin To: Scott Long Date: Wed, 26 Oct 2005 13:24:02 -0400 User-Agent: KMail/1.8.2 References: <435EEC56.9080708@samsco.org> <200510261130.45506.jhb@freebsd.org> <435FA6A9.4000600@samsco.org> In-Reply-To: <435FA6A9.4000600@samsco.org> MIME-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Content-Disposition: inline Message-Id: <200510261324.03790.jhb@freebsd.org> Cc: freebsd-hackers@freebsd.org Subject: Re: [Fwd: Re: use of bus_dmamap_sync] X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 26 Oct 2005 17:23:35 -0000 On Wednesday 26 October 2005 11:54 am, Scott Long wrote: > > Perhaps on i386. Each arch implements sync(). Argh, it does look like > > the memory barriers needed on e.g., Alpha aren't used with static buffers > > because of the map != NULL check in sys/busdma.h. *sigh* I guess archs > > that need membars even without bounce buffers need to always allocate and > > setup a bus_dmamap. None of that matters for i386 though. > > Feel free to fix alpha. Again, long ago, I thought that alpha pretended > to be coherent in the 2GB DMA window that we use so that it could be > more like i386. If that's not true then that's fine. If you need to > make structural changes to the MI code on order to fix alpha, please let > me know. No, I'm just a moron. Alpha uses the nobounce_map for static buffers, so bus_dmamap_sync will use the appropriate membars. -- John Baldwin <>< http://www.FreeBSD.org/~jhb/ "Power Users Use the Power to Serve" = http://www.FreeBSD.org