From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [PATCH] RESEND: SCSI, libata: add support for ATA_16 commands to libata ATAPI devices Date: Thu, 01 Feb 2007 17:35:53 +0900 Message-ID: <45C1A669.5000206@gmail.com> References: <200701021935.07840.liml@rtr.ca> <200701311346.26644.liml@rtr.ca> <45C1356B.6000907@gmail.com> <45C1377F.6070001@rtr.ca> <45C1A424.5040805@garzik.org> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1 Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <45C1A424.5040805@garzik.org> Sender: linux-scsi-owner@vger.kernel.org To: Jeff Garzik Cc: Mark Lord , Linux IDE , James Bottomley , linux-scsi@vger.kernel.org List-Id: linux-ide@vger.kernel.org Jeff Garzik wrote: > Mark Lord wrote: >> 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? > > Speaking strictly about the device, IDENTIFY PACKET DEVICE data page > tells us whether the device supports 12-byte or 16-byte CDBs. No need > to guess. > > Some host controllers only support 12-byte, but I think that most should > support 16-byte. Out of curiosity, does ATA controllers which don't allow 16byte CDB actually exist? It's transferred using PIO protocol anyway. -- tejun