From mboxrd@z Thu Jan 1 00:00:00 1970 From: Sergei Shtylyov Subject: Re: [PATCH] pata_it8213: MWDMA0 is unsupported Date: Thu, 26 Nov 2009 21:47:03 +0300 Message-ID: <4B0ECD27.7050302@ru.mvista.com> References: <200911261728.36433.bzolnier@gmail.com> <200911261903.01199.bzolnier@gmail.com> <4B0EC52B.2070805@ru.mvista.com> <200911261927.00597.bzolnier@gmail.com> <4B0EC9EA.9000608@ru.mvista.com> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from gateway-1237.mvista.com ([206.112.117.35]:4748 "HELO imap.sh.mvista.com" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with SMTP id S1750867AbZKZSqF (ORCPT ); Thu, 26 Nov 2009 13:46:05 -0500 In-Reply-To: <4B0EC9EA.9000608@ru.mvista.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Bartlomiej Zolnierkiewicz Cc: Alan Cox , linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org Hello, I wrote: >>>>>>>> MWDMA0 timings cannot be met with the PIIX based controller >>>>>>>> programming interface. >>>>>>>> This change should be safe as this is how we have been doing >>>>>>>> things in IDE it8213 host driver for years. >>>>>>>> Signed-off-by: Bartlomiej Zolnierkiewicz >>>>>>>> --- >>>>>>>> Verified with the documentation (similar case as with pata_efar). >>>>>>> Uhhh, no... >>>>>>> Too many damn drivers. >>>>>>> Too much damn duplication. >>>>>>> Too much damn subtle differences here and there. >>>>>>> The hardware is probably fine for MWMDA0 when it comes to >>>>>>> pata_{efar,it8213}, >>>>>>> it just not documented properly in the data sheet. >>>>>> How so with pata_efar? The active/recovery bitfields are still >>>>>> 2-bit wide, no? >>>>> Yes but when TIMEx bit is disabled we are using XFER_PIO_SLOW timings. >>> 600 ns cycle vs spec'ed 480 ns? Is it really worth it? >> 960 ns actually > That table you're looking at (probably in the SLC90E66 datasheet?) > must be screwed up. 960 ns is used for command cycles, according to > Intel's docs, data cycles run at 600 ns... Well, after doublke checking 82371AB datasheet has 660 ns, and ICH PRM has 900 ns. Not sure where I got what I've cited now, perhaps in some older version of PRM... what a mess indeed. :-/ MBR, Sergei