Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265668AbUFSBCY (ORCPT ); Fri, 18 Jun 2004 21:02:24 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266758AbUFRT6h (ORCPT ); Fri, 18 Jun 2004 15:58:37 -0400 Received: from stat1.steeleye.com ([65.114.3.130]:18069 "EHLO hancock.sc.steeleye.com") by vger.kernel.org with ESMTP id S266787AbUFRT5W (ORCPT ); Fri, 18 Jun 2004 15:57:22 -0400 Subject: Re: DMA API issues From: James Bottomley To: Ian Molton Cc: David Brownell , Linux Kernel , greg@kroah.com, tony@atomide.com, jamey.hicks@hp.com, joshua@joshuawise.com In-Reply-To: <20040618204438.35278560.spyro@f2s.com> 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> Content-Type: text/plain Content-Transfer-Encoding: 7bit X-Mailer: Ximian Evolution 1.0.8 (1.0.8-9) Date: 18 Jun 2004 14:57:01 -0500 Message-Id: <1087588627.2134.155.camel@mulgrave> Mime-Version: 1.0 Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 681 Lines: 19 On Fri, 2004-06-18 at 14:44, Ian Molton wrote: > > For example, if usbaudio uses usb_buffer_alloc to stream data, > > that eliminates dma bouncing. That's dma_alloc_coherent at > > its core ... it should allocate from that 32K region. > > Agreed. There are complications to this: not all platforms can access PCI memory directly. That's why ioremap and memcpy_toio and friends exist. What should happen on these platforms? James - 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/