Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S265930AbUFWQJ0 (ORCPT ); Wed, 23 Jun 2004 12:09:26 -0400 Received: (majordomo@vger.kernel.org) by vger.kernel.org id S266096AbUFWQIM (ORCPT ); Wed, 23 Jun 2004 12:08:12 -0400 Received: from cantor.suse.de ([195.135.220.2]:749 "EHLO Cantor.suse.de") by vger.kernel.org with ESMTP id S265930AbUFWQGM (ORCPT ); Wed, 23 Jun 2004 12:06:12 -0400 Date: Wed, 23 Jun 2004 18:01:04 +0200 Message-ID: From: Takashi Iwai To: Russell King Cc: Linus Torvalds , Jeff Garzik , Matt Porter , Jamey Hicks , Ian Molton , linux-kernel@vger.kernel.org, greg@kroah.com, tony@atomide.com, david-b@pacbell.net, joshua@joshuawise.com Subject: Re: DMA API issues In-Reply-To: <20040623164419.E27549@flint.arm.linux.org.uk> References: <20040618122112.D3851@home.com> <20040618204322.C17516@flint.arm.linux.org.uk> <20040622000838.B7802@flint.arm.linux.org.uk> <40D7941F.3020909@pobox.com> <20040623133423.B27549@flint.arm.linux.org.uk> User-Agent: Wanderlust/2.10.1 (Watching The Wheels) SEMI/1.14.5 (Awara-Onsen) FLIM/1.14.5 (Demachiyanagi) APEL/10.6 MULE XEmacs/21.4 (patch 15) (Security Through Obscurity) (i386-suse-linux) MIME-Version: 1.0 (generated by SEMI 1.14.5 - "Awara-Onsen") Content-Type: text/plain; charset=US-ASCII Sender: linux-kernel-owner@vger.kernel.org X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 1377 Lines: 36 At Wed, 23 Jun 2004 16:44:19 +0100, Russell King wrote: > > On Wed, Jun 23, 2004 at 05:36:57PM +0200, Takashi Iwai wrote: > > > and a similar one for the ARM-specific "write combining" case (for > > > framebuffers utilising the DMA API)? > > > > pgprot_noncached() is used on many other architectures in fbmem.c > > (well, not really, but the result is identical). > > Should it be provided as another one, or is it used as default in > > dma_mmap_coherent()? > > The whole point is to kill the idea that drivers should have to know > about page protection crap. That should be wholely contained within > the architecture implementation. I agree. My question is whether we need to handle different cases with cached, non-cached and writecombine, according to the demand of the driver. In other words, do we always handle these mmap pages to be non-cached (except for writecombine version)? > > Also, it would be nice to have a version for sg-buffer, too. > > Well, we don't have a sg-buffer version of dma_alloc_coherent(), > so we don't have a sg-buffer version of dma_mmap_coherent(). That sound reasonable :) Takashi - 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/