From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Bottomley Subject: Re: [PATCH] set a base index for libsas based ata devices Date: Tue, 20 Dec 2016 10:30:34 -0800 Message-ID: <1482258634.2475.20.camel@HansenPartnership.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset="UTF-8" Content-Transfer-Encoding: 7bit Return-path: Received: from bedivere.hansenpartnership.com ([66.63.167.143]:47502 "EHLO bedivere.hansenpartnership.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1756379AbcLTSbP (ORCPT ); Tue, 20 Dec 2016 13:31:15 -0500 In-Reply-To: Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Peter Chang , "linux-scsi@vger.kernel.org" , linux-ide@vger.kernel.org On Tue, 2016-12-20 at 10:15 -0800, Peter Chang wrote: > we discovered this when futzing w/ the queue depth parameter for ata > disks behind the pm8006 controller. setting depth == 1 should disable > ncq, but the sysfs part silently fails and we continue sending the > fpdma command variants. no one else probably cares about the > disabling ncq path, but we do like to test. I'd actually disagree with this assertion; it's why tagging (what you mean by ncq) and queue depth are separate. Queue depth represents the number of outstanding commands we sent on the wire; however, it often excludes things like sense probes and error handling commands, so tagged depth==1 is a different operating environment from untagged. Some transports actually have no untagged variant nowadays, so it's physically impossible to disable tagging. James > anyway, adding both the ide and scsi lists because i'm not quite sure > there's a separate libsas list and a single commit seems better for > this.