From mboxrd@z Thu Jan 1 00:00:00 1970 From: Jeff Garzik Subject: Re: [PATCH 4/5] ide: Add support for TRIM Date: Wed, 08 Apr 2009 10:59:46 -0400 Message-ID: <49DCBBE2.4050506@garzik.org> 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> <49DCB5A5.7040100@rtr.ca> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from srv5.dvmed.net ([207.36.208.214]:42986 "EHLO mail.dvmed.net" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S932142AbZDHO7w (ORCPT ); Wed, 8 Apr 2009 10:59:52 -0400 In-Reply-To: <49DCB5A5.7040100@rtr.ca> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Mark Lord Cc: Matthew Wilcox , linux-ide@vger.kernel.org, linux-kernel@vger.kernel.org, jgarzik@redhat.com, David Woodhouse Mark Lord wrote: > 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. It's a list of LBA ranges, like the NV-cache stuff recently added. Jeff