From owner-freebsd-usb@FreeBSD.ORG Wed Feb 1 06:33:01 2006 Return-Path: X-Original-To: freebsd-usb@freebsd.org Delivered-To: freebsd-usb@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [216.136.204.125]) by hub.freebsd.org (Postfix) with ESMTP id 0A49A16A420 for ; Wed, 1 Feb 2006 06:33:01 +0000 (GMT) (envelope-from peterjeremy@optushome.com.au) Received: from mail28.syd.optusnet.com.au (mail28.syd.optusnet.com.au [211.29.133.169]) by mx1.FreeBSD.org (Postfix) with ESMTP id 3BB0043D46 for ; Wed, 1 Feb 2006 06:32:59 +0000 (GMT) (envelope-from peterjeremy@optushome.com.au) Received: from turion.vk2pj.dyndns.org (c220-239-19-236.belrs4.nsw.optusnet.com.au [220.239.19.236]) by mail28.syd.optusnet.com.au (8.12.11/8.12.11) with ESMTP id k116Wu2C016128 (version=TLSv1/SSLv3 cipher=EDH-RSA-DES-CBC3-SHA bits=168 verify=NO); Wed, 1 Feb 2006 17:32:57 +1100 Received: from turion.vk2pj.dyndns.org (localhost.vk2pj.dyndns.org [127.0.0.1]) by turion.vk2pj.dyndns.org (8.13.4/8.13.4) with ESMTP id k116Wuk2001112; Wed, 1 Feb 2006 17:32:56 +1100 (EST) (envelope-from peter@turion.vk2pj.dyndns.org) Received: (from peter@localhost) by turion.vk2pj.dyndns.org (8.13.4/8.13.4/Submit) id k116Wsg2001111; Wed, 1 Feb 2006 17:32:55 +1100 (EST) (envelope-from peter) Date: Wed, 1 Feb 2006 17:32:54 +1100 From: Peter Jeremy To: Ian Dowse Message-ID: <20060201063254.GD678@turion.vk2pj.dyndns.org> References: <20060131194244.GA75983@saturn.kn-bremen.de> <200601312200.aa58422@nowhere.iedowse.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline In-Reply-To: <200601312200.aa58422@nowhere.iedowse.com> X-PGP-Key: http://members.optusnet.com.au/peterjeremy/pubkey.asc User-Agent: Mutt/1.5.11 Cc: Juergen Lock , freebsd-usb@freebsd.org Subject: Re: cvs commit: src/sys/dev/usb ehci.c ehci_pci.c ehcivar.h X-BeenThere: freebsd-usb@freebsd.org X-Mailman-Version: 2.1.5 Precedence: list List-Id: FreeBSD support for USB List-Unsubscribe: , List-Archive: List-Post: List-Help: List-Subscribe: , X-List-Received-Date: Wed, 01 Feb 2006 06:33:01 -0000 On Tue, 2006-Jan-31 22:00:21 +0000, Ian Dowse wrote: >In the case of USB, there is actually no need for it to perform >large contiguous allocations because the host controllers all support >some limited scatter-gather functionality so they can mostly access >the caller's memory buffer directly via bus_dmamap_load(). This is >something I implemented a year or to ago but I haven't got around >to finishing the last few details of the patch yet. I'd looked into the specs far enough to determine that this was possible but haven't looked at how difficult it would be to implement it. I think this is a preferable solution and would be interested in helping you finish your patch. Whilst it's desirable that contigmalloc() not panic, making contigmalloc() return NULL when asked to allocate a large block of memory without waiting doesn't actually help get the data from the physical device into the driver. -- Peter Jeremy