From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [PATCH] libata: implement and use DMA mask configuration helper Date: Mon, 09 Apr 2007 04:47:35 -0400 Message-ID: <4619FDA7.10007@garzik.org> References: <20070309104945.GG32687@htj.dyndns.org> <45F155E3.9040604@garzik.org> <45FD5154.9040603@gmail.com> <45FD7B44.5040509@garzik.org> <4619ECB7.9060601@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from srv5.dvmed.net ([207.36.208.214]:52777 "EHLO mail.dvmed.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1750999AbXDIIrh (ORCPT ); Mon, 9 Apr 2007 04:47:37 -0400 In-Reply-To: <4619ECB7.9060601@gmail.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Tejun Heo Cc: linux-ide@vger.kernel.org Tejun Heo wrote: > Jeff, there are further problems with doing pci_go_64() only on devices > which support 64bit. pci_set_dma_mask() is the only place where the PCI > code can test whether DMA is usable or not, so if we don't configure DMA > mask on 32bit controllers, there's no way to tell whether DMA is allowed > on the controller/bus or not. We end up blindly enabling bus mastering > without consulting the PCI bus. > > I think it's just cleaner to do pci_configure_dma_masks() on all cases > with proper DMA mask. There is always a cleaner solution :) My implementation is based on current practice for all 64-bit drivers. If you wish to change current practice, that is another matter... Jeff