From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCHSET #upstream-fixes] libata: improve flaky link handling Date: Fri, 30 Jan 2009 08:57:00 +0900 Message-ID: <4982424C.3010709@kernel.org> References: <1233228696-10562-1-git-send-email-tj@kernel.org> <87f94c370901290607t4cef87ack43fd456d1703d1ca@mail.gmail.com> <4981D02A.8030001@rtr.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: Received: from hera.kernel.org ([140.211.167.34]:54107 "EHLO hera.kernel.org" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752335AbZA2X5S (ORCPT ); Thu, 29 Jan 2009 18:57:18 -0500 In-Reply-To: <4981D02A.8030001@rtr.ca> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Mark Lord Cc: Greg Freemyer , jeff@garzik.org, linux-ide@vger.kernel.org Hello, Mark, Greg. Mark Lord wrote: > Greg Freemyer wrote: >> On Thu, Jan 29, 2009 at 6:31 AM, Tejun Heo wrote: >>> So, with abundant link quality problems, the following problems have >>> been identified. >> >> This looks like an important patchset for those of us that use eSata. >> Any chance these can get into the opensuse 11.1 kernels? Or lacking >> that, the os factory kernels? I do agree it's something I'd like to see deployed fast but I'm not really sure. Any change is dangerous and nothing sucks more than when a machine fails to boot after a update and I did that at least once already. :-( I'll surely get the first patch into the tree but for the rest I think I'll wait a bit. > Based on experience here, I'd say the problem isn't terribly widespread > beyond the specific vendor Tejun identified. I have several eSATA setups > at hand here, and never see flaky link behaviour on them. Based on my experience with PMPs and these drives, problems like these are not really dependent on which device or controller is at the end of the cabling but depends on the length and quality of cabling. The controller - device combination does have some influence, especially on 3Gbps but I didn't find the WD drives to be exceptionally fragile other than the shutdown-after-transmission-error problem. I'm using about 30cm of internal cable + sata-eSATA gender + ~2M eSATA cable and it's not too difficult to cause problem with any device with such cabling. The cabling is on the extreme side (may even be out of spec) but given the bug reports I get for eSATA devices including PMPs, I don't think this kind of cabling is unfortunately not too uncommon. As I wrote before, what makes it worse is the stiffness of the eSATA cable, I can easily cause enough wiggle at the connectors by touching the cable and it easily makes the device crap out especially at 3Gbps. Thanks. -- tejun