From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergei Shtylyov Subject: Re: [PATCH] ide: Fix ata_id_has_dword_io to return DWORD I/O support properly Date: Sat, 20 Dec 2008 16:25:05 +0300 Message-ID: <494CF231.4020000@ru.mvista.com> References: <494A5BBF.8000807@inf.tu-dresden.de> <494A837A.50801@garzik.org> <20081218181015.2e160d5c@lxorguk.ukuu.org.uk> <494C512B.6090304@shaw.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from gateway-1237.mvista.com ([63.81.120.155]:10113 "EHLO imap.sh.mvista.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1750933AbYLTNZM (ORCPT ); Sat, 20 Dec 2008 08:25:12 -0500 In-Reply-To: <494C512B.6090304@shaw.ca> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Robert Hancock Cc: linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org Hello. Robert Hancock wrote: >>> This seems like a risky assumption... >> >> Its wrong on various counts >> >> - ata_id_major_version can't tell early ATA versions apart >> - on anything later than the early ISA IDE paddles (the ones that >> basically were just bus decoders) its invisible to the drive >> >> Except for legacy ISA bus controllers (and even there it is >> questionable) >> I would favour simply ignoring it. > > 32-bit IO wouldn't work on any ISA controller, would it? What happens > if you do 32-bit IO port access on something on the ISA bus? TTBOM, depending on what's driven by device on -IOCS16, this will translate into 2, 3, or 4 cycles at the successive addresses. In case of the IDE data register, this should translate into one 16-bit cycle at 0x1x0, one 8-bit cycle at 0x1x1, and one 8-bit cycle at 0x1x2 which is of course not what anybody would want... WBR, Sergei