From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: ide-io.c, ide_do_request -- race condition? Date: Fri, 16 Jul 2004 03:06:30 -0400 Sender: linux-ide-owner@vger.kernel.org Message-ID: <40F77E76.70501@pobox.com> References: <40F2CFDE.66D28904@verizon.net> <20040712183505.GE26789@bounceswoosh.org> <40F72B6A.6F12F454@verizon.net> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from parcelfarce.linux.theplanet.co.uk ([195.92.249.252]:21179 "EHLO www.linux.org.uk") by vger.kernel.org with ESMTP id S266501AbUGPHGn (ORCPT ); Fri, 16 Jul 2004 03:06:43 -0400 In-Reply-To: <40F72B6A.6F12F454@verizon.net> List-Id: linux-ide@vger.kernel.org To: "Max T. Woodbury" Cc: "Eric D. Mudama" , linux-ide@vger.kernel.org Max T. Woodbury wrote: > "Eric D. Mudama" wrote: > >>On Mon, Jul 12 at 13:52, Max T. Woodbury wrote: >> >>>Still, why would PIO mode be unsafe? (I can see slower, but I don't >>>expect speed from this beast. Oh well. Thanks for the pointer.) >> >>PIO has no data integrity check, so bogus cables that glitch the data >>will not be detected. Not sure if that is what he was talking about, >>but is definitely a problem for PIO. > > > Huh? Unless something major has changed since the last time I looked at > DMA hardware (and it has been a few years), DMA uses the same transfer > sequence from the devices point of view as PIO. The fact that the Ultra DMA does CRC, PIO does not. Thus will cable glitches be detected. Jeff