From mboxrd@z Thu Jan 1 00:00:00 1970 From: Markus Lidel Subject: Re: I2O enhancement for Adaptec management software Date: Thu, 08 Apr 2004 11:27:52 +0200 Sender: linux-scsi-owner@vger.kernel.org Message-ID: <40751B18.9040403@shadowconnect.com> References: <40712A47.4090903@shadowconnect.com> <1081159378.4679.1.camel@laptop.fenrus.com> <20040405110524.A3987@infradead.org> <20040405101007.GA27710@devserv.devel.redhat.com> <20040405111245.A4077@infradead.org> <1081370204.1747.5.camel@mulgrave> Mime-Version: 1.0 Content-Type: text/plain; charset=us-ascii; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from [213.133.118.2] ([213.133.118.2]:13026 "EHLO mail.shadowconnect.com") by vger.kernel.org with ESMTP id S261654AbUDHJ0Q (ORCPT ); Thu, 8 Apr 2004 05:26:16 -0400 In-Reply-To: <1081370204.1747.5.camel@mulgrave> List-Id: linux-scsi@vger.kernel.org To: James Bottomley Cc: Christoph Hellwig , Arjan van de Ven , SCSI Mailing List Hello, James Bottomley wrote: >>SG_IO is for scsi passthrough. now you could invent fake scsi command >>opcodes for native messages, but at that point it starts to get silly. > Actually, no it's not. SG_IO will to IDE taskfile passthrough just as > well. As arjan says, it's for native command passthrough. > Now, since the dpt_i20 commontly accepts SCSI commands it would have to > have some way to distinguish these "native" commands from other SCSI > commands, but surely a vendor specific service action would do that. The patch is for i2o_config, not for dpt_i2o! These are different drivers and have (from the architecture view) not much in common. dpt_i2o is a driver which let access to the disks entirely using the SCSI subsystem. The i2o subsystem uses i2o_core and i2o_block to access disks (which doesn't use SCSI at all), and also have an SCSI driver, which let access to each connected disk (i2o_scsi). But the i2o_scsi is not needed for normal disk access. It's very funny, that i copied the patch 1:1 from dpt_i2o, where it is used too, and nobody ever complained about it :-D But don't understand me wrong, if there is a better way to do it, i'll try to do it this way. > The consummate advantage is that we don't have to have the driver trying > to construct the SG list on its own (which is what about 50% of this > patch is doing), it can use the block layer to do that on a passed in > area of application memory. Than i have to move the patch to the i2o_scsi driver, because the i2o_scsi uses the SCSI subsystem already. But IMHO the i2o_config driver is better suited, cause the patch is only needed for the management software. One last question, could i use the SG list building function without using the SCSI layer? Thank you very much. Best regards, Markus Lidel ------------------------------------------ Markus Lidel (Senior IT Consultant) Shadow Connect GmbH Carl-Reisch-Weg 12 D-86381 Krumbach Germany Phone: +49 82 82/99 51-0 Fax: +49 82 82/99 51-11 E-Mail: Markus.Lidel@shadowconnect.com URL: http://www.shadowconnect.com