From mboxrd@z Thu Jan 1 00:00:00 1970 From: Mark Lord Subject: Re: [BUG] libahci returns stale result tf much of the time. Date: Mon, 04 Oct 2010 15:51:15 -0400 Message-ID: <4CAA3033.8030405@teksavvy.com> References: <4C9C3878.9010206@teksavvy.com> <4C9C44D0.1030409@teksavvy.com> <4C9CA385.5090709@teksavvy.com> <4C9CA673.4090104@teksavvy.com> <4C9D33C0.8050900@gmail.com> <4CA99BCB.8080904@gmail.com> <4CAA0885.8060906@teksavvy.com> <4CAA0996.5080403@teksavvy.com> <4CAA0F6C.6080609@teksavvy.com> <4CAA21F4.5060000@teksavvy.com> <4CAA2AA6.2010204@pobox.com> <4CAA2C6F.2090603@teksavvy.com> <4CAA2E16.4010905@pobox.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8; format=flowed Content-Transfer-Encoding: 7bit Return-path: Received: from ironport2-out.teksavvy.com ([206.248.154.183]:4805 "EHLO ironport2-out.pppoe.ca" rhost-flags-OK-OK-OK-FAIL) by vger.kernel.org with ESMTP id S1755926Ab0JDTvR (ORCPT ); Mon, 4 Oct 2010 15:51:17 -0400 In-Reply-To: <4CAA2E16.4010905@pobox.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Jeff Garzik Cc: Tejun Heo , Robert Hancock , Seed , IDE/ATA development list On 10-10-04 03:42 PM, Jeff Garzik wrote: > On 10/04/2010 03:35 PM, Mark Lord wrote: >> Yeah. Non-data commands still get a (correct) updated result_tf from AHCI, >> but data commands don't get one, unless they fail. >> >> Weird, but I've worked around it now. > > Might be that we just get a single-bit "OK" notification from hardware for successfully completed commands, a la NCQ's SDB FIS. > > Which opcodes are you using? I see set-acoustic-mgmt in one email... opcode 0xec : IDENTIFY The result_tf it receives is from whatever non-data command last preceeds it. So if the previous non-data command failed (eg. hdparm -Z), then the IDENTIFY command actually works, but appears to fail. Cheers