From owner-freebsd-hackers@FreeBSD.ORG Thu Feb 17 19:31:49 2005 Return-Path: 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 65F0D16A4CE for ; Thu, 17 Feb 2005 19:31:49 +0000 (GMT) Received: from relay03.pair.com (relay03.pair.com [209.68.5.17]) by mx1.FreeBSD.org (Postfix) with SMTP id BCC4D43D39 for ; Thu, 17 Feb 2005 19:31:48 +0000 (GMT) (envelope-from silby@silby.com) Received: (qmail 45346 invoked from network); 17 Feb 2005 19:31:47 -0000 Received: from unknown (HELO localhost) (unknown) by unknown with SMTP; 17 Feb 2005 19:31:47 -0000 X-pair-Authenticated: 209.68.2.70 Date: Thu, 17 Feb 2005 13:31:46 -0600 (CST) From: Mike Silbersack To: Gerald Heinig In-Reply-To: <4214D6A0.9010803@syskonnect.de> Message-ID: <20050217133029.U43225@odysseus.silby.com> References: <4214D6A0.9010803@syskonnect.de> MIME-Version: 1.0 Content-Type: TEXT/PLAIN; charset=US-ASCII; format=flowed cc: hackers@freebsd.org Subject: Re: bus_dmamem_alloc strangeness X-BeenThere: freebsd-hackers@freebsd.org X-Mailman-Version: 2.1.1 Precedence: list List-Id: Technical Discussions relating to FreeBSD List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Thu, 17 Feb 2005 19:31:49 -0000 On Thu, 17 Feb 2005, Gerald Heinig wrote: > Hi hackers, > > I've come across weird behaviour in bus_dmamem_alloc() whilst trying to > allocate small memory blocks (less than PAGE_SIZE) which have to be > aligned to PAGE_SIZE. > My segment size is 2048, my maximum number of segments is 1 (it MUST be > contiguous), my max. total segment size is also 2048 and my alignment > constraint is 4k (PAGE_SIZE). However, the DMA memory I'm getting from > bus_dmamem_alloc() is NOT aligned to 4k. You should e-mail Scott Long (scottl@freebsd.org) about this directly. I believe that he has been working on related changes to busdma recently, but I'm not sure which branches have received his improvements. Mike "Silby" Silbersack