From mboxrd@z Thu Jan 1 00:00:00 1970 Return-Path: Received: from mtagate1.de.ibm.com ([195.212.29.150]:15621 "EHLO mtagate1.de.ibm.com") by vger.kernel.org with ESMTP id S965247AbWIROIQ (ORCPT ); Mon, 18 Sep 2006 10:08:16 -0400 Subject: Re: [PATCH 2/6] Introduce CONFIG_ZONE_DMA From: Martin Schwidefsky Reply-To: schwidefsky@de.ibm.com In-Reply-To: <20060918135559.GB15096@infradead.org> References: <20060911222729.4849.69497.sendpatchset@schroedinger.engr.sgi.com> <20060911222739.4849.79915.sendpatchset@schroedinger.engr.sgi.com> <20060918135559.GB15096@infradead.org> Content-Type: text/plain Date: Mon, 18 Sep 2006 16:08:07 +0200 Message-Id: <1158588487.31364.3.camel@localhost> Mime-Version: 1.0 Content-Transfer-Encoding: 7bit Sender: linux-arch-owner@vger.kernel.org To: Christoph Hellwig Cc: Christoph Lameter , linux-mm@vger.kernel.org, Nick Piggin , linux-ia64@vger.kernel.org, Marcelo Tosatti , Arjan van de Ven , Martin Bligh , KAMEZAWA Hiroyuki , Andi Kleen , linux-arch@vger.kernel.org List-ID: On Mon, 2006-09-18 at 14:55 +0100, Christoph Hellwig wrote: > > Second, arches may use ZONE_DMA in an unknown way. We set CONFIG_ZONE_DMA > > for all arches that do not set CONFIG_GENERIC_ISA_DMA in order to insure > > backwards compatibility. The arches may later undefine ZONE_DMA > > if their arch code has been verified to not depend on ZONE_DMA. > > Let's pass this on to linux-arch so that the arch maintainers can give input > whether they need ZONE_DMA or not. If this just sneaks in unseen I'd bet > various architectures will just keept it around despite not needing it. s390 needs ZONE_DMA for the memory area below 2GB. That is required for the control structure of channel based I/O. It is not ISA but conceptually related. Can we rename GENERIC_ISA_DMA into GENERIC_IO_DMA or something similar? -- blue skies, Martin. Martin Schwidefsky Linux for zSeries Development & Services IBM Deutschland Entwicklung GmbH "Reality continues to ruin my life." - Calvin.