From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [PATCH] RESEND: SCSI, libata: add support for ATA_16 commands to libata ATAPI devices Date: Thu, 01 Feb 2007 03:28:45 -0500 Message-ID: <45C1A4BD.3030909@garzik.org> References: <200701021935.07840.liml@rtr.ca> <200701311346.26644.liml@rtr.ca> <45C1356B.6000907@gmail.com> <45C1377F.6070001@rtr.ca> <45C138E8.1040706@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=ISO-8859-1; format=flowed Content-Transfer-Encoding: 7bit Return-path: In-Reply-To: <45C138E8.1040706@gmail.com> Sender: linux-scsi-owner@vger.kernel.org To: Tejun Heo Cc: Mark Lord , Linux IDE , James Bottomley , linux-scsi@vger.kernel.org List-Id: linux-ide@vger.kernel.org Tejun Heo wrote: > SCSI always uses the smallest command it can use, so we're safe. Most > other commands are issued directly from the userland and it's their > responsibility not to feed disallowed commands to a device (or we need > more advanced filter). Anyways, this has never been guaranteed because > the limit is host wide. > > So, I'm for setting it to 16. Jeff, what do you think? Like I just noted in another email, the limit is really on the /device/ side. In theory the user could plug in a 16-byte ATAPI device and a 12-byte ATAPI device to the same host. We should be able to safely raise the limit to 16-byte for most host controllers. Note I said "most". The bitch will be figuring out which host controllers do not like 16-byte CDBs. Jeff