From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Bottomley Subject: Re: Question about Request Sense case in scsi_lib.c Date: 12 Oct 2004 12:13:13 -0500 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <1097601199.2044.91.camel@mulgrave> References: <20041012000058.GA26569@osdl.org> <20041012165919.GA27526@osdl.org> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: Received: from stat16.steeleye.com ([209.192.50.48]:45968 "EHLO hancock.sc.steeleye.com") by vger.kernel.org with ESMTP id S266349AbUJLRNa (ORCPT ); Tue, 12 Oct 2004 13:13:30 -0400 In-Reply-To: <20041012165919.GA27526@osdl.org> List-Id: linux-scsi@vger.kernel.org To: Dave Olien Cc: Tim Pepper , SCSI Mailing List On Tue, 2004-10-12 at 11:59, Dave Olien wrote: > Thanks for the feedback. Yes, Automatic volume transfer is on, and I > was expecting there'd be poor performance as a result. I just > didn't expect to get IO errors. The odd thing is that the "bus reset" > leads to the SCSI request being requeued. But every once in a while, > the requeue fails with errors and the request is failed. I'll look at > these cases a little more closely, try to understand why the requeues fail. Hang on a minute ... if you're ping pong'ing the drives using AVT, those transfers take time to achieve. The device is probably returning UNIT ATTENTION, NOT_READY while the transfer is in progress. This is probably the source of the requeue. As for the error, I still don't understand that, but it looks like something went wrong in setting up or tearing down the dma mapping, so that it was incorrectly described when this happened a second time. James