Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265945AbUFTVAG (ORCPT ); Sun, 20 Jun 2004 17:00:06 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S265946AbUFTVAG (ORCPT ); Sun, 20 Jun 2004 17:00:06 -0400 Received: from crl-mail.crl.dec.com ([192.58.206.9]:62127 "EHLO crl-mailb.crl.dec.com") by vger.kernel.org with ESMTP id S265945AbUFTVAB (ORCPT ); Sun, 20 Jun 2004 17:00:01 -0400 Message-ID: <40D5FAC7.7060601@hp.com> Date: Sun, 20 Jun 2004 16:59:51 -0400 From: Jamey Hicks User-Agent: Mozilla Thunderbird 0.5 (X11/20040229) X-Accept-Language: en-us, en MIME-Version: 1.0 To: James Bottomley CC: Ian Molton , david-b@pacbell.net, Linux Kernel , greg@kroah.com, tony@atomide.com, joshua@joshuawise.com Subject: Re: DMA API issues References: <1087582845.1752.107.camel@mulgrave> <20040618193544.48b88771.spyro@f2s.com> <1087584769.2134.119.camel@mulgrave> <20040618195721.0cf43ec2.spyro@f2s.com> <40D34078.5060909@pacbell.net> <20040618204438.35278560.spyro@f2s.com> <1087588627.2134.155.camel@mulgrave> <20040619002522.0c0d8e51.spyro@f2s.com> <1087601363.2078.208.camel@mulgrave> <20040619005106.15b8c393.spyro@f2s.com> <1087603453.2135.224.camel@mulgrave> <20040619011416.64d16c4e.spyro@f2s.com> <1087616990.2078.240.camel@mulgrave> In-Reply-To: <1087616990.2078.240.camel@mulgrave> Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit X-HPLC-MailScanner-Information: Please contact the ISP for more information X-HPLC-MailScanner: Found to be clean X-HPLC-MailScanner-SpamCheck: not spam (whitelisted), SpamAssassin (score=-3.508, required 5, BAYES_00 -4.90, NO_STRINGS 1.39) Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1183 Lines: 43 James Bottomley wrote: >On Fri, 2004-06-18 at 19:14, Ian Molton wrote: > > >>On 18 Jun 2004 19:04:11 -0500 >>James Bottomley wrote: >> >> >> >>>Because the piece of memory you wish to access is bus remote. >>> >>> >>No, its *not* >> >>my CPU can write there directly. >> >>no strings attached. >> >>the DMA API just only understands how to map from RAM, not anything >>else. >> >> > >I think you'll actually find that it is. OHCI is a device (representing >a USB hub), it's attached to the system by some interface that >constitutes a bus (the bus interface transforming the CPU access cycles >to device access cycles, translating interrupts etc.). > > > Bus remote is a red herring in this case. The only difference between this case and the ones supported by the coherent_dma_mask is that the constraint on placement of the allocated memory cannot be encoded as a bitmask. Jamey - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/