From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: Early ATA devices Date: Wed, 01 Aug 2007 15:02:36 +0900 Message-ID: <46B021FC.20507@gmail.com> References: <20070801014137.4ab39e94@the-village.bc.nu> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from rv-out-0910.google.com ([209.85.198.189]:50482 "EHLO rv-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1754772AbXHAGCm (ORCPT ); Wed, 1 Aug 2007 02:02:42 -0400 Received: by rv-out-0910.google.com with SMTP id k20so85362rvb for ; Tue, 31 Jul 2007 23:02:41 -0700 (PDT) In-Reply-To: <20070801014137.4ab39e94@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, jeff@garzik.org Alan Cox wrote: > So I've been doing a scan of the code versus the early ATA specifications > (English translation not the original Latin ;)) > > I've found a couple of problem cases we don't deal with but I'm not sure > matter, and an inconsistency > > #1 We assume identify works. Early ATA actually lists this command > as optional > #2 We don't allow for INIT_DEV_PARAMS failing which it may do on > some early IDE pre ATA devices > > and the inconsistency > > We check ATA < 4 || non-LBA capable when deciding whether to issue > INIT_DEV_PARAMS. ATA 4+ however mandate LBA so the second case isn't > theoretically at least possible. > > Aside from those cases the command issue (but not the detection paths) > appear to be clean for everything from ST412 upwards providing a drive is > being used in 16 head mode and does its own write precompensation > selection. > > So in theory we can persuade libata to drive original MFM/RLL disks with > relatively few changes Does anyone have a working device to test? -- tejun