From mboxrd@z Thu Jan  1 00:00:00 1970
Return-Path: <linux-kernel-owner@vger.kernel.org>
Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand
	id S1758130AbcG0S5r (ORCPT <rfc822;w@1wt.eu>);
	Wed, 27 Jul 2016 14:57:47 -0400
Received: from smtp02.citrix.com ([66.165.176.63]:16953 "EHLO
	SMTP02.CITRIX.COM" rhost-flags-OK-OK-OK-OK) by vger.kernel.org
	with ESMTP id S1758221AbcG0S5h (ORCPT
	<rfc822;linux-kernel@vger.kernel.org>);
	Wed, 27 Jul 2016 14:57:37 -0400
X-IronPort-AV: E=Sophos;i="5.28,430,1464652800"; 
   d="scan'208";a="375846292"
Subject: Re: [Xen-devel] [GIT PULL] xen: features and fixes for 4.8-rc0
To: Linus Torvalds <torvalds@linux-foundation.org>,
        David Vrabel <dvrabel@cantab.net>,
        Shannon Zhao <shannon.zhao@linaro.org>,
        "Rafael J. Wysocki" <rafael.j.wysocki@intel.com>
References: <5798BB14.9090606@cantab.net>
 <CA+55aFyYXv6VkO4=7PjsT0H1dvaa6Byftkc=2VpHg9GN7RbpqQ@mail.gmail.com>
CC: xen-devel <xen-devel@lists.xenproject.org>,
        "linux-kernel@vger.kernel.org" <linux-kernel@vger.kernel.org>
From: Andrew Cooper <andrew.cooper3@citrix.com>
Message-ID: <d1538de2-5819-7d67-4e6e-00564bbcbe2b@citrix.com>
Date: Wed, 27 Jul 2016 19:57:34 +0100
User-Agent: Mozilla/5.0 (X11; Linux x86_64; rv:45.0) Gecko/20100101
 Icedove/45.1.0
MIME-Version: 1.0
In-Reply-To: <CA+55aFyYXv6VkO4=7PjsT0H1dvaa6Byftkc=2VpHg9GN7RbpqQ@mail.gmail.com>
Content-Type: text/plain; charset="utf-8"
Content-Transfer-Encoding: 7bit
X-DLP: MIA1
Sender: linux-kernel-owner@vger.kernel.org
List-ID: <linux-kernel.vger.kernel.org>
X-Mailing-List: linux-kernel@vger.kernel.org

On 27/07/16 19:42, Linus Torvalds wrote:
> On Wed, Jul 27, 2016 at 6:45 AM, David Vrabel <dvrabel@cantab.net> wrote:
>> Shannon Zhao (16):
>>       Xen: ACPI: Hide UART used by Xen
> So this caused a trivial conflict. No biggie, it wasn't bad and the
> patch was acked by Rafael. However, looking at it made me somewhat
> unhappy.
>
> Should the device entry in ACPI really be hidden unconditionally? In
> particular, if we are *not* running under virtualization, it sounds
> wrong to hide it.
>
> Comments? Am I missing something?

The purpose of the ACPI STAO table (Status Override table, ratified in
ACPI 6.0) is to list items elsewhere in the ACPI namespace which should
be completely ignored.  It is used in cases where it is impossible or
prohibitive to edit the system AML.

The patch itself only hides the UART if instructed to do so by the STAO
table (last hunk).

~Andrew