From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [PATCH] libata ATAPI transfer size cleanups Date: Thu, 01 Nov 2007 05:54:06 -0400 Message-ID: <4729A23E.7000601@garzik.org> References: <20071101090733.GA9258@havoc.gtf.org> <20071101094344.6eb9d8bc@the-village.bc.nu> 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]:34436 "EHLO mail.dvmed.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756648AbXKAJyI (ORCPT ); Thu, 1 Nov 2007 05:54:08 -0400 In-Reply-To: <20071101094344.6eb9d8bc@the-village.bc.nu> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Alan Cox Cc: linux-ide@vger.kernel.org, LKML Alan Cox wrote: > On Thu, 1 Nov 2007 05:07:33 -0400 > Jeff Garzik wrote: > >> This is purely for comment and testing, not for merging (yet?). >> >> A common recipe in several vendor drivers (either GPL'd, or I have NDA'd >> access to use them as a documentation-like reference) for ATAPI was >> slightly different from ours. This recipe can be found in >> atapi_tf_xfer_size(), and it's slightly different from Alan's. > > Looks mostly good. Might cause breakage on one or two controllers by > setting lbam/lbah to 0 for DMA but we can test that and find out. DMA always zeroed lbam/lbah thanks to memset(), my patch merely made it explicit. > Note however - the scheme in use now has been tested for over ten years > in drivers/ide. The scheme below has not... See my other email just posted, differences and errata abound :) Jeff