From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [PATCH/RFC] libata: turn on the ATAPI DMA DIR support per word 62 Date: Fri, 07 Apr 2006 02:47:33 -0400 Message-ID: <44360B05.6050509@garzik.org> References: <44360922.8050801@tw.ibm.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]:47559 "EHLO mail.dvmed.net") by vger.kernel.org with ESMTP id S932318AbWDGGri (ORCPT ); Fri, 7 Apr 2006 02:47:38 -0400 In-Reply-To: <44360922.8050801@tw.ibm.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: albertl@mail.com Cc: linux-ide@vger.kernel.org, Jonathan Benson , Tejun Heo , Carlos Pardo , Doug Maxey Albert Lee wrote: > Turn on the ATAPI DMA DIR support if word 62 indicates it. > > Signed-off-by: Albert Lee > --- > ATAPI DMA DIR follow-up patch to turn on the DMA_DIR support automatically > by checking identify device word 62. (Thanks for Jeff and Tejun's pointer.) > > According to Jonathan's test result, SiI 3611 (the current known bridge that > requires the ATAPI DMA DIR support) doesn't implement word 62. So, the > atapi_dmadir parameter is preserved to enable the DMA DIR support manually as > work around. Two comments: * I would like to find a device that's compliant with the spec, and test the patch, before committing. * DMADIR not only includes a bit flag indicating its presence, it also moves all the DMA capability bits from their standard places. You'll have to audit every place that reads dev->id[]'s mwdma/udma masks and make sure they look at the DMADIR-special-case location, when DMADIR is set. Jeff