From mboxrd@z Thu Jan 1 00:00:00 1970 From: Tejun Heo Subject: Re: [BUG] libahci returns stale result tf much of the time. Date: Mon, 04 Oct 2010 11:18:03 +0200 Message-ID: <4CA99BCB.8080904@gmail.com> References: <4C9C3878.9010206@teksavvy.com> <4C9C44D0.1030409@teksavvy.com> <4C9CA385.5090709@teksavvy.com> <4C9CA673.4090104@teksavvy.com> <4C9D33C0.8050900@gmail.com> Mime-Version: 1.0 Content-Type: text/plain; charset=UTF-8 Content-Transfer-Encoding: 7bit Return-path: Received: from mail-fx0-f46.google.com ([209.85.161.46]:38667 "EHLO mail-fx0-f46.google.com" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1752814Ab0JDJSJ (ORCPT ); Mon, 4 Oct 2010 05:18:09 -0400 Received: by fxm14 with SMTP id 14so1560204fxm.19 for ; Mon, 04 Oct 2010 02:18:08 -0700 (PDT) In-Reply-To: <4C9D33C0.8050900@gmail.com> Sender: linux-ide-owner@vger.kernel.org List-Id: linux-ide@vger.kernel.org To: Robert Hancock Cc: Mark Lord , Seed , Jeff Garzik , IDE/ATA development list Hello, On 09/25/2010 01:26 AM, Robert Hancock wrote: >> And here's an example of the bug, which should work (as a demo) >> for most folks out there with the same controller ahci / JMB360: >> >> Here, I'll use hdparm to do a "set acoustic" command >> on a drive which does NOT have the "Acoustic Management" feature set. >> Just look for the fd fd fd strings in the returned data, >> and notice how the final IDENTIFY at the end works, but returns >> bad ATA status 0x51 from the stale result_tf: > > The d2h_fis area is supposed to be updated by the controller with > the last FIS received from the device. Maybe this controller just > isn't doing that for some reason? Hmm... one possibility is that the controller takes some time to update the area and the driver is reading it off too early. Maybe adding a delay would resolve the issue? Mark, do you know whether this problem is isolated to JMB360? Thanks. -- tejun