From mboxrd@z Thu Jan 1 00:00:00 1970 From: Michael Tokarev Subject: disable TCQ? Date: Thu, 28 Jun 2007 12:19:33 +0400 Message-ID: <46836F15.2040208@msgid.tls.msk.ru> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from hobbit.corpit.ru ([81.13.94.6]:20434 "EHLO hobbit.corpit.ru" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1760139AbXF1ITf (ORCPT ); Thu, 28 Jun 2007 04:19:35 -0400 Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: linux-scsi@vger.kernel.org /sys/block/sdX/device/queue_depth file is read-write with libsata, but is read-only with SCSI controllers (at least with the ones we have -- mostly aic7xxx or mptsas). Googling for "disable tcq" gives results about {dis,en}abling TCQ at boot time, and also mentions ipr (which we don't have). Is there an option to control TCQ at runtime? I'm doing a set of (pretty interesting) tests of various drives and their TCQ/NCQ implementations, everything's simple on SATA front but I can't test different TCQ modes with SCSI drives because I can't find a way control TCQ at runtime, and since those are production machines (I plug/unplug spare drives for testing, but have no spare machines), I can't reboot them often. Thanks. /mjt