From owner-freebsd-hackers@FreeBSD.ORG Fri Dec 1 05:30:47 2006 Return-Path: X-Original-To: freebsd-hackers@freebsd.org Delivered-To: freebsd-hackers@freebsd.org Received: from mx1.FreeBSD.org (mx1.freebsd.org [69.147.83.52]) by hub.freebsd.org (Postfix) with ESMTP id BD84516C333 for ; Fri, 1 Dec 2006 05:28:11 +0000 (UTC) (envelope-from kamalpr@gmail.com) Received: from nf-out-0910.google.com (nf-out-0910.google.com [64.233.182.185]) by mx1.FreeBSD.org (Postfix) with ESMTP id 8202043CAB for ; Fri, 1 Dec 2006 05:27:58 +0000 (GMT) (envelope-from kamalpr@gmail.com) Received: by nf-out-0910.google.com with SMTP id x37so3270210nfc for ; Thu, 30 Nov 2006 21:28:09 -0800 (PST) DomainKey-Signature: a=rsa-sha1; q=dns; c=nofws; s=beta; d=gmail.com; h=received:message-id:date:from:sender:to:subject:in-reply-to:mime-version:content-type:references:x-google-sender-auth; b=RwvuXRtxvaqK7YJsEUiOyC2jXxLsqCIf3GPt/Bx9flgxbi2ft4Topx2P1XlXupCEiO3FZSZRzG0bML3VokdAz1rHwZbN8gkbxYMKHMhxGqdmELg6iOwmL1pDSH/jERkHOJU5JthuVzwoFCpmlNa63xSgUsyLxs/RdRJcezrMbXI= Received: by 10.82.126.5 with SMTP id y5mr982818buc.1164950889303; Thu, 30 Nov 2006 21:28:09 -0800 (PST) Received: by 10.82.171.6 with HTTP; Thu, 30 Nov 2006 21:28:09 -0800 (PST) Message-ID: Date: Fri, 1 Dec 2006 10:58:09 +0530 From: "Kamal R. Prasad" Sender: kamalpr@gmail.com To: freebsd-hackers@freebsd.org In-Reply-To: <44A87163.1020203@elischer.org> MIME-Version: 1.0 References: <200607021305.aa75873@nowhere.iedowse.com> <44A87163.1020203@elischer.org> X-Google-Sender-Auth: 97226a1a98ffaf1c Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Content-Disposition: inline X-Content-Filtered-By: Mailman/MimeDel 2.1.5 Subject: Re: contiguous memory allocation problem 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: Fri, 01 Dec 2006 05:30:47 -0000 Hello, I would like to unsubscribe myself from all freebsd mailing lists. I have sent an unsubscribe to freebsd-hackers-unsubscribe, but did not get any response to verify. Since the admin is on the mailing list, I would appreciate if you can delete my name and/or email me the procedure to follow. thanks -kamal On 7/3/06, Julian Elischer wrote: > > Ian Dowse wrote: > > >In message <200607021138.11945.hselasky@c2i.net>, Hans Petter Selasky > writes: > > > > > >>But there is one problem, that has been overlooked, and that is High > speed > >>isochronous transfers, which are not supported by the existing USB > system. I > >>don't think that the EHCI specification was designed for scatter and > gather, > >>when you consider this: > >> > >>8 transfers of 0xC00 bytes has to fit on 7 pages. If this is going to > work, > >>and I am right, one page has to contain two transfers. (see page 43 of > >>ehci-r10.pdf) > >> > >> > > > >I haven't looked into the details, but the text in section 3.3.3 > >seems to suggest that EHCI is designed to not require physically > >contiguous allocations here either, so the same approach of using > >bus_dmamap_load() should work: > > > > This data structure requires the associated data buffer to be > > contiguous (relative to virtual memory), but allows the physical > > memory pages to be non-contiguous. Seven page pointers are provided > > to support the expression of 8 isochronous transfers. The seven > > pointers allow for 3 (transactions) * 1024 (maximum packet size) > > * 8 (transaction records) (24576 bytes) to be moved with this > > data structure, regardless of the alignment offset of the first > > page. > > > > > > yes, as long as the beffers are contiguous in some virtual space then > the maximum number of pages they > can need is 7. > (they actually fit into 6 but they may start part way through the first > page and may therefore overflow into a 7th). > > >Ian > >_______________________________________________ > >freebsd-hackers@freebsd.org mailing list > >http://lists.freebsd.org/mailman/listinfo/freebsd-hackers > >To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org > " > > > > > _______________________________________________ > freebsd-hackers@freebsd.org mailing list > http://lists.freebsd.org/mailman/listinfo/freebsd-hackers > To unsubscribe, send any mail to "freebsd-hackers-unsubscribe@freebsd.org" >