From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCH] ata: libata depends on HAS_DMA Date: Fri, 15 May 2009 14:31:11 +0900 Message-ID: <4A0CFE1F.5080409@gmail.com> References: <20090513043409.GA13577@cynthia.pants.nu> <20090513095127.308b00e7@lxorguk.ukuu.org.uk> <4A0B5E5A.4090906@gmail.com> <20090514091928R.fujita.tomonori@lab.ntt.co.jp> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from mail-gx0-f166.google.com ([209.85.217.166]:51795 "EHLO mail-gx0-f166.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754073AbZEOFaE (ORCPT ); Fri, 15 May 2009 01:30:04 -0400 In-Reply-To: <20090514091928R.fujita.tomonori@lab.ntt.co.jp> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: FUJITA Tomonori Cc: hancockrwd@gmail.com, alan@lxorguk.ukuu.org.uk, flar@allandria.com, schmitz@biophys.uni-duesseldorf.de, arnd@arndb.de, linux-kernel@vger.kernel.org, jgarzik@pobox.com, linux-ide@vger.kernel.org, takata@linux-m32r.org, geert@linux-m68k.org, linux-m68k@vger.kernel.org, ysato@users.sourceforge.jp FUJITA Tomonori wrote: > On Wed, 13 May 2009 17:57:14 -0600 > Robert Hancock wrote: > >> Alan Cox wrote: >>>>> If it doesn't interfere with plain PIO mode, fine. >>>> I agree. There definitely needs to still be support for IDE ports that >>>> don't have DMA capability. >>> There is - it's just if the platform doesn't implement the dma_* APIs you >>> get a problem. >> Wouldn't the easiest solution be to just dummy out the DMA API calls on >> this platform to always fail? That would fix these compile problems.. > > Can libata call dma_supported() per device to decide DMA or PIO mode? > Then, we can solve this problem by add dummy DMA API (just calls BUG) > on such architectures, without Kconfig magic or adding ifdef (like the > old ide stack does), I think. Sure it can. Which specific drivers are we talking about? Thanks. -- tejun