From mboxrd@z Thu Jan 1 00:00:00 1970 From: Douglas Gilbert Subject: Re: [PATCH as468] Retry supposedly "unrecoverable" hardware errors Date: Thu, 17 Feb 2005 14:27:41 +1000 Message-ID: <42141D3D.9080800@torque.net> References: Reply-To: dougg@torque.net Mime-Version: 1.0 Content-Type: text/plain; charset=US-ASCII; format=flowed Content-Transfer-Encoding: 7bit Received: from borg.st.net.au ([65.23.158.22]:25277 "EHLO borg.st.net.au") by vger.kernel.org with ESMTP id S262133AbVBQE1E (ORCPT ); Wed, 16 Feb 2005 23:27:04 -0500 In-Reply-To: Sender: linux-scsi-owner@vger.kernel.org List-Id: linux-scsi@vger.kernel.org To: Alan Stern Cc: James Bottomley , Martin Peschke , Radovan Garabik , SCSI development list Alan Stern wrote: > James: > > This is an updated and unmangled version of the patch sent in by Martin > Peschke. Apparently some drives report Hardware Error sense for > problems which do improve after retrying, so the patch retries these > supposedly "unrecoverable" errors for such devices. Recent SPC-3 and SBC-2 drafts treat the sense keys of MEDIUM ERROR and HARDWARE ERROR in a similar way. Both can return an "info" field which has the same meaning (lba of first failure). The distinction is that MEDIUM ERROR is a little more precise (at least for magnetic rotating media) **. For flash ram the distinction is moot. I believe MEDIUM ERROR and HARDWARE ERROR should be treated the same way in scsi_check_sense() (i.e. both return NEEDS_RETRY). That way an extra black list category is avoided. ** HARDWARE ERROR is returned in cases of self diagnostic failure and lack of available blocks for reassignment. It seems valid for a device to return a HARDWARE ERROR sense key both for these cases and unrecoverable data errors (and ignore MEDIUM ERROR). Doug Gilbert