From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Lord Subject: Re: [PATCH 02/02] sata_mv: workaround for multi_count errata sata24 Date: Mon, 13 Apr 2009 11:44:01 -0400 Message-ID: <49E35DC1.2090007@rtr.ca> References: <49E359D6.1090309@rtr.ca> <49E35A5E.4020204@rtr.ca> <20090413164034.20f1695a@lxorguk.ukuu.org.uk> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from rtr.ca ([76.10.145.34]:39300 "EHLO mail.rtr.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751863AbZDMPoD (ORCPT ); Mon, 13 Apr 2009 11:44:03 -0400 In-Reply-To: <20090413164034.20f1695a@lxorguk.ukuu.org.uk> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Alan Cox Cc: Jeff Garzik , IDE/ATA development list Alan Cox wrote: > On Mon, 13 Apr 2009 11:29:34 -0400 > Mark Lord wrote: > >> Workaround for errata SATA#24 in sata_mv. >> This errata affects WRITE_MULTI* commands when >> the device multi_count produces a DRQ block size >= 4Kbytes. >> >> We work around it here by converting such operations >> into ordinary PIO_WRITEs instead. >> >> Note that this might result in a PIO FUA write unavoidably being converted >> into a non-FUA write. In practice, any system using FUA is also going to be >> using DMA rather than PIO, so this shouldn't affect anyone in the real world. > > You can just screen the FUA bit from the identify data when you do the > drive setup to avoid that bit. .. I think doing it at identify time would prevent DMA FUA commands, which are fine in sata_mv. So the only place to really hit it exactly, is at command construction or issue time. cheers