From mboxrd@z Thu Jan 1 00:00:00 1970 From: Albert Lee Subject: Re: ATA tape drive STT3401A needs DRQ HSM workaround too Date: Tue, 13 Nov 2007 18:08:04 +0800 Message-ID: <47397784.9070205@tw.ibm.com> References: <471C6C44.2030607@gmail.com> <471CEDD4.5040201@garzik.org> <471D25D0.9020702@rtr.ca> Reply-To: albertl@mail.com Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: Received: from e35.co.us.ibm.com ([32.97.110.153]:49439 "EHLO e35.co.us.ibm.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1751533AbXKMKIO (ORCPT ); Tue, 13 Nov 2007 05:08:14 -0500 Received: from d03relay02.boulder.ibm.com (d03relay02.boulder.ibm.com [9.17.195.227]) by e35.co.us.ibm.com (8.13.8/8.13.8) with ESMTP id lADA8DnO006773 for ; Tue, 13 Nov 2007 05:08:13 -0500 Received: from d03av03.boulder.ibm.com (d03av03.boulder.ibm.com [9.17.195.169]) by d03relay02.boulder.ibm.com (8.13.8/8.13.8/NCO v8.5) with ESMTP id lADA8DJ6119724 for ; Tue, 13 Nov 2007 03:08:13 -0700 Received: from d03av03.boulder.ibm.com (loopback [127.0.0.1]) by d03av03.boulder.ibm.com (8.12.11.20060308/8.13.3) with ESMTP id lADA8CWd029557 for ; Tue, 13 Nov 2007 03:08:13 -0700 In-Reply-To: <471D25D0.9020702@rtr.ca> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Mark Lord , Jeff Garzik Cc: Tejun Heo , linux-ide@vger.kernel.org, Alan Cox Mark Lord wrote: > Man.. somebody needs to teach hald the difference between optical drives > and tape drives.. It seems to just sit in a tight loop issuing the same > failed commands over and over and over to the tape unit after boot. > > I had to kill it off to gain control of Fedora so I could actually *do* > anything on the system. > > Weird. > > Any, Albert Lee has claimed the drive. > Thanks for the drive. After playing with the drive and checking the log, the DRQ+ERR problem only happens when the tape drive is doing REQUEST SENSE. Also the DRQ=1 ERR=1 situation only happens when the tape drive wants us to transfer the CDB, not the data. It looks like the ERR=1 here is the residue of the previous command/error: After an error and receiving the next PACKET command, the drive actually wants the host to transfer the CDB of the next command (i.e. request sense) by setting DRQ=1, but somehow it forgets to clear ERR to 0... Maybe we can ignore the ERR bit if the command is REQUEST SENSE. Patch to follow. -- albert