Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S266531AbUFVCHQ (ORCPT ); Mon, 21 Jun 2004 22:07:16 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266539AbUFVCHQ (ORCPT ); Mon, 21 Jun 2004 22:07:16 -0400 Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:53891 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id S266531AbUFVCGn (ORCPT ); Mon, 21 Jun 2004 22:06:43 -0400 Message-ID: <40D7941F.3020909@pobox.com> Date: Mon, 21 Jun 2004 22:06:23 -0400 From: Jeff Garzik User-Agent: Mozilla/5.0 (X11; U; Linux i686; en-US; rv:1.6) Gecko/20040510 X-Accept-Language: en-us, en MIME-Version: 1.0 To: Russell King CC: Takashi Iwai , Matt Porter , Jamey Hicks , Ian Molton , linux-kernel@vger.kernel.org, greg@kroah.com, tony@atomide.com, david-b@pacbell.net, joshua@joshuawise.com, Linus Torvalds Subject: Re: DMA API issues References: <20040618175902.778e616a.spyro@f2s.com> <20040618110721.B3851@home.com> <40D3356E.8040800@hp.com> <20040618122112.D3851@home.com> <20040618204322.C17516@flint.arm.linux.org.uk> <20040622000838.B7802@flint.arm.linux.org.uk> In-Reply-To: <20040622000838.B7802@flint.arm.linux.org.uk> Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1021 Lines: 27 Russell King wrote: > On Mon, Jun 21, 2004 at 03:35:42PM +0200, Takashi Iwai wrote: >>Yes, the struct page pointer is needed for vma_ops.nopage in mmap on >>ALSA. So far, this is broken on some architectures like ARM. We need >>a proper conversion from virtual/bus pointer to a page struct. > > > Please get away from your nopage implementation. We've been around this > before with Linus, and the conclusion was that it's up to architectures > to provide a MMAP method for DMA memory, which _may_ use the nopage > method if and only if it is appropriate for their implementation. Can you elaborate? When I was writing sound/oss/via82cxxx_audio.c, Linus specifically recommended using ->nopage, which worked out quite well (modulo cleaning up VM_xxx flags). Jeff - 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/