From mboxrd@z Thu Jan 1 00:00:00 1970 From: Bartlomiej Zolnierkiewicz Subject: Re: [PATCH 3/20] dtc2278: ->io_32bit setting don't have to be identical for master/slave Date: Mon, 10 Dec 2007 00:15:15 +0100 Message-ID: <200712100015.15735.bzolnier@gmail.com> References: <200712092208.58494.bzolnier@gmail.com> <20071209222736.1c4ba88c@the-village.bc.nu> Mime-Version: 1.0 Content-Type: text/plain; charset="iso-8859-1" Content-Transfer-Encoding: 7bit Return-path: Received: from ug-out-1314.google.com ([66.249.92.171]:54126 "EHLO ug-out-1314.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751021AbXLIXG2 (ORCPT ); Sun, 9 Dec 2007 18:06:28 -0500 Received: by ug-out-1314.google.com with SMTP id z38so1397527ugc for ; Sun, 09 Dec 2007 15:06:27 -0800 (PST) In-Reply-To: <20071209222736.1c4ba88c@the-village.bc.nu> Content-Disposition: inline Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Alan Cox Cc: linux-ide@vger.kernel.org On Sunday 09 December 2007, Alan Cox wrote: > > drive->io_32bit is used per PIO transfer so there is no reason to > > require it to be identical for master/slave. > > Sure about that ? > > The driver has always gone to great pains to ensure that occurs and that > suggests the author had a good reason for doing it. Have you tested this > with an actual DTC2278 card ? > > If not - NAK. You risk corruptors for no material benefit. There is absolutely no hardware setup done by IDE subsystem or dtc2278 host driver when ->io_32bit setting is changed and since ->io_32bit setting is only ever checked per drive / PIO transfer so this is currently purely a software limitation (moreover HDIO_DRIVE_CMD and HDIO_DRIVE_TASKFILE ioctls force 16-bit I/O anyway). [ I also haven't noticed anything related to this requirement in Winbond W83759A datasheet (though I have only quickly skimmed through it)... ] Bart