From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Lord Subject: Re: [PATCH] RESEND: SCSI, libata: add support for ATA_16 commands to libata ATAPI devices Date: Wed, 31 Jan 2007 19:42:39 -0500 Message-ID: <45C1377F.6070001@rtr.ca> References: <200701021935.07840.liml@rtr.ca> <200701311346.26644.liml@rtr.ca> <45C1356B.6000907@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from rtr.ca ([64.26.128.89]:4463 "EHLO mail.rtr.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1030511AbXBAAml (ORCPT ); Wed, 31 Jan 2007 19:42:41 -0500 In-Reply-To: <45C1356B.6000907@gmail.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Tejun Heo Cc: Linux IDE , James Bottomley , Jeff Garzik , linux-scsi@vger.kernel.org Tejun Heo wrote: > Mark Lord wrote: >.. >> So, to achieve ATA passthru capability for libata ATAPI, >> we have to instead use the ATA_16 opcode: a 16-byte command. >> >> SCSI normally disallows issuing 16-byte commands to 12-byte devices, >> so special support has to be added for this. > I might have missed the discussion but can't we just set > host->max_cmd_len to 16 unconditionally? Sure thing, if you and Jeff are happy with that, then lets do it. I just kind of assumed that the complexity in ata_set_port_max_cmd_len() was there for some kind of reason. For example, I think all existing ATAPI drives only speak 12-byte packet protocols, and so if we tell SCSI we're good for 16-byte, then won't the SCSI layer suddenly start sending us READ_16 and the like? Cheers