From mboxrd@z Thu Jan 1 00:00:00 1970 From: James Bottomley Subject: Re: [PATCH] libata: rewrite SCSI host scheme to be one per ATA host Date: Wed, 22 Apr 2009 19:27:25 +0000 Message-ID: <1240428445.3431.22.camel@mulgrave.int.hansenpartnership.com> References: <20090422090929.GA14928@havoc.gtf.org> <49EEE225.3010700@garzik.org> <49EF0A92.1070400@panasas.com> <49EF337F.1030804@ngrt.de> <20090422161856.1251f8a0@lxorguk.ukuu.org.uk> <1240414622.3431.14.camel@mulgrave.int.hansenpartnership.com> <49EF63A6.8040103@garzik.org> Mime-Version: 1.0 Content-Type: text/plain Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <49EF63A6.8040103@garzik.org> Sender: linux-kernel-owner@vger.kernel.org To: Jeff Garzik Cc: Alan Cox , Daniela Engert , Boaz Harrosh , linux-ide@vger.kernel.org, linux-scsi@vger.kernel.org, LKML , Jens Axboe , Tejun Heo List-Id: linux-ide@vger.kernel.org On Wed, 2009-04-22 at 14:36 -0400, Jeff Garzik wrote: > James Bottomley wrote: > > On Wed, 2009-04-22 at 16:18 +0100, Alan Cox wrote: > >>> Don't forget, there are ATAPI devices (some Sony CD burners and old > >>> phase-changers come into mind) which *do* have multiple LUNs sitting > >>> beyond the PATA port. I don't know if libata supports such setups (my > >>> old OS/2 driver does) but one shouldn't hijack LUNs to emulate targets. > >> It's a long time ago since I tested it but my 5 CD changer was correctly > >> supported by libata (or more accurately by sr...). > > > > Well, sr supports the discovered CD/DVD; ch is the actual changer > > manager. Usually ch attaches to one LUN and sr attaches to another. > > Like Alan's, if I understand him correctly, my PATA ATAPI CD changer > simply presents a bunch of addressible LUNs. I never loaded, nor seemed > to need, ch. Yes, they both seem to be non standard changer implementations that just present as many CDs as they could chage to. The ch is actually a driver for devices which conform to the SCSI Media Changer standard, which tends to present LUN zero as the smc device and LUN1 as the selected CD/DVD > I should boot a current libata and see how it behaves... Might be fun. James