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: Fri, 19 Dec 2008 14:31:35 +0300 Message-ID: <494B8617.3020808@ru.mvista.com> References: <494A5BBF.8000807@inf.tu-dresden.de> <494A837A.50801@garzik.org> <494A8768.4080100@ru.mvista.com> <200812182142.16533.bzolnier@gmail.com> <20081218224010.45e3ce55@lxorguk.ukuu.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from h155.mvista.com ([63.81.120.155]:51221 "EHLO imap.sh.mvista.com" rhost-flags-OK-FAIL-OK-FAIL) by vger.kernel.org with ESMTP id S1751355AbYLSLbl (ORCPT ); Fri, 19 Dec 2008 06:31:41 -0500 In-Reply-To: <20081218224010.45e3ce55@lxorguk.ukuu.org.uk> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Alan Cox Cc: Bartlomiej Zolnierkiewicz , Jeff Garzik , Mario Schwalbe , linux-kernel@vger.kernel.org, Linux IDE mailing list Hello. Alan Cox wrote: >> OTOH the current patch is safe even for 2.6.28 (based on years of experience >> with the check that we had in IDE subsystem) and will fix some libata drivers >> (pata_legacy, pata_qdi and pata_winbond) to use dword IO on >= ATA-2 devices. >> >> [ In reality this a regression fix for IDE -> libata conversion as it is a >> huge performance improvement for the above mentioned DMA-less drivers. ] >> > > The 32bit PIO support is already queued up and went to Jeff a while ago > so thats all in hand - its btw a big win on some suprising chipset cases > including Intel ICH chipsets. > This is indeed strange... >> Jeff, I would like to merge it through IDE tree since the other patch depends >> on it but if you want to go ahead and push it to Linus earlier feel free to >> do it (or I can include it into the next IDE fixes pull request if you like). >> > > Its still broken. You cannot use the version check for versions below 3. > The word is reserved since ATA-2, and ata_id_major_version() should be returning 0 for pre-ATA-3 drives, so I don't know what else can be done here... > I remain unconvinced we should be looking at it anywhere except specific > pure ISA cycle pass through hardware and thus it belongs as a helper for > I'm still not getting how drive can support or not support "DWORD I/O" -- you certainly can't have 32-bit I/O cycle on ISA (only on EISA) and you certainly cannot translate 32-bit cycle to the ATA bus. I remember I had some hypotheses before but they turned out to be inconsistent. > those drivers not as ata_has_mumble stuff as its not ATA - eide_* maybe. > Indeed, already ATA-1 says that the word 48 is "includedfor backwards compatible VU use". > Alan > MBR, Sergei