From mboxrd@z Thu Jan 1 00:00:00 1970 From: Doug Ledford Subject: Re: [PATCH] 2.4.19 scsi_rescan patch (2nd pass) Date: Wed, 2 Oct 2002 12:56:06 -0400 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <20021002165606.GF30234@redhat.com> References: Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii Return-path: Content-Disposition: inline In-Reply-To: List-Id: linux-scsi@vger.kernel.org To: "Cress, Andrew R" Cc: 'James Bottomley' , linux-scsi@vger.kernel.org On Wed, Oct 02, 2002 at 09:40:06AM -0700, Cress, Andrew R wrote: > James, > > A user-space hotplug event can't be guaranteed to have enough information in > all cases. > Possible cases: > 1) Administrator "knows" and manually issues a hot-plug command. > 2) A daemon detects a SAF-TE or SES event by slot number. > Not sure if we can really determine what we need from just a slot > number? > 3) Other external disk enclosure (JBOD) that doesn't expose a > SAF-TE or SES interface. > This case is out in the cold without the kernel-level rescan. > > I'm disregarding case (1), since my target customer environment won't > tolerate the manual step. You can forget 3 as well. It's simply not reasonable to tie up a busy bus with very long selection timeouts to "poll scan" a bus for new insertions. Not gonna happen. If the JBOD doesn't expose a reasonable interface, then hot plug with it isn't supported in linux. If it exposes something other than SAF-TE or SES then the protocol it does support needs to be added to the daemon in #2 in order for it to be supported. -- Doug Ledford 919-754-3700 x44233 Red Hat, Inc. 1801 Varsity Dr. Raleigh, NC 27606