From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: ata_ram driver Date: Thu, 06 Mar 2008 17:21:58 +0900 Message-ID: <47CFA9A6.2040506@gmail.com> References: <20080222200951.GI16995@parisc-linux.org> <47BF3E54.9050609@rtr.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: Received: from gv-out-0910.google.com ([216.239.58.187]:3886 "EHLO gv-out-0910.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752450AbYCFIWJ (ORCPT ); Thu, 6 Mar 2008 03:22:09 -0500 Received: by gv-out-0910.google.com with SMTP id s4so1409418gve.37 for ; Thu, 06 Mar 2008 00:22:06 -0800 (PST) In-Reply-To: <47BF3E54.9050609@rtr.ca> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Mark Lord Cc: Matthew Wilcox , linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org Mark Lord wrote: > Matthew Wilcox wrote: >> I've ported the scsi_ram driver [1] to libata. It could use a lot more >> work -- there's a lot of stuff in the identify page that I haven't >> filled in, and there's a lot of commands it doesn't even try to execute. >> >> For example, when you unload the driver, you get the mildly disturbing >> messages: >> >> sd 12:0:0:0: [sdb] Stopping disk >> sd 12:0:0:0: [sdb] START_STOP FAILED >> sd 12:0:0:0: [sdb] Result: hostbyte=DID_BAD_TARGET >> driverbyte=DRIVER_OK,SUGGEST_OK >> > .. > > I see messages like those with *established* libata drivers from time to > time. > It could just be a bug in the shutdown sequence, somewhere between libata, > SCSI, block layer, and the device model in general. Or not. It's because of the sequence of events. Currently, driver unload sequence is the same as when the device is hot unplugged. libata detects that the device is gone and disables it and report it to SCSI layer. SCSI layer takes over and tries to kill the SCSI device and tell sd to shutdown and sd issues START_STOP to shutdown which fails w/ DID_BAD_TARGET because the matching ATA device is already gone. I've left it that way because I'm not sure whether spinning down the drive on driver unload is the correct thing to do. The message is annoying tho. Thanks. -- tejun