From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: sata_nv + ADMA + Samsung disk problem Date: Wed, 02 Jan 2008 13:57:41 -0500 Message-ID: <477BDEA5.8040701@garzik.org> References: <20070808120804.GB5257@boogie.lpds.sztaki.hu> <20080101164416.GA29574@boogie.lpds.sztaki.hu> <477B0429.7040909@gmail.com> <477B0CFD.1030603@shaw.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from srv5.dvmed.net ([207.36.208.214]:35796 "EHLO mail.dvmed.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752568AbYABS5t (ORCPT ); Wed, 2 Jan 2008 13:57:49 -0500 In-Reply-To: Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Allen Martin Cc: Robert Hancock , Tejun Heo , Gabor Gombas , linux-kernel@vger.kernel.org, linux-ide@vger.kernel.org, Kuan Luo , Peer Chen Allen Martin wrote: >> The question I had for NVIDIA regarding this that I never got >> answered >> was, is there any reason why we would need a delay when switching >> between NCQ and non-NCQ commands on ADMA, and if not, is >> there any known >> cause that could cause the controller to get into this seemingly >> locked-up state? > > When switching from NCQ to non NCQ or vice versa you must make sure all > outstanding commands are completed before issuing the new command. The > hardware doesn't do anything to prevent queued and non queued commands > from going out on the wire at the same time which will certainly cause > some drives to fail. The software definitely provides that guarantee for all NCQ-capable controllers. Jeff