From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Lord Subject: Re: [PATCH 4/5] ide: Add support for TRIM Date: Wed, 08 Apr 2009 10:33:09 -0400 Message-ID: <49DCB5A5.7040100@rtr.ca> References: <1238683047-13588-1-git-send-email-willy@linux.intel.com> <1238683047-13588-2-git-send-email-willy@linux.intel.com> <1238683047-13588-3-git-send-email-willy@linux.intel.com> <1238683047-13588-4-git-send-email-willy@linux.intel.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from rtr.ca ([76.10.145.34]:51594 "EHLO mail.rtr.ca" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752080AbZDHOdL (ORCPT ); Wed, 8 Apr 2009 10:33:11 -0400 In-Reply-To: <1238683047-13588-4-git-send-email-willy@linux.intel.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Matthew Wilcox Cc: linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org, jgarzik@redhat.com, David Woodhouse Matthew Wilcox wrote: > From: David Woodhouse > > Signed-off-by: David Woodhouse > [modified to reduce amount of special casing needed for discard] > Signed-off-by: Matthew Wilcox > --- .. > + task->tf.command = ATA_CMD_DSM; > + task->tf.feature = ATA_DSM_TRIM; > + task->tf.hob_feature = 0x00; > + task->tf.nsect = size / 512; > + task->tf.hob_nsect = (size / 512) >> 8; .. Matthew (or others), Could you perhaps explain what the purpose of the data portion of this command is for? The draft ATA spec I have here has mangled text in the description -- like it's missing a crucial sentence there. So it's not obvious exactly why this command even needs data to be transfered. Thanks