From mboxrd@z Thu Jan  1 00:00:00 1970
From: Andrew Cooper <andrew.cooper3@citrix.com>
Subject: Re: [RFC 2/8] x86/acpi: Warn about multiple HPET tables
Date: Tue, 5 Nov 2013 16:03:10 +0000
Message-ID: <527916BE.1010408@citrix.com>
References: <1383591286-19976-1-git-send-email-andrew.cooper3@citrix.com>
	<1383591286-19976-3-git-send-email-andrew.cooper3@citrix.com>
	<5278DD7A02000078000FF76B@nat28.tlf.novell.com>
Mime-Version: 1.0
Content-Type: text/plain; charset="us-ascii"
Content-Transfer-Encoding: 7bit
Return-path: <xen-devel-bounces@lists.xen.org>
Received: from mail6.bemta3.messagelabs.com ([195.245.230.39])
	by lists.xen.org with esmtp (Exim 4.72)
	(envelope-from <Andrew.Cooper3@citrix.com>) id 1Vdj6W-0005rU-Oh
	for xen-devel@lists.xenproject.org; Tue, 05 Nov 2013 16:03:44 +0000
In-Reply-To: <5278DD7A02000078000FF76B@nat28.tlf.novell.com>
List-Unsubscribe: <http://lists.xen.org/cgi-bin/mailman/options/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=unsubscribe>
List-Post: <mailto:xen-devel@lists.xen.org>
List-Help: <mailto:xen-devel-request@lists.xen.org?subject=help>
List-Subscribe: <http://lists.xen.org/cgi-bin/mailman/listinfo/xen-devel>,
	<mailto:xen-devel-request@lists.xen.org?subject=subscribe>
Sender: xen-devel-bounces@lists.xen.org
Errors-To: xen-devel-bounces@lists.xen.org
To: Jan Beulich <JBeulich@suse.com>
Cc: xen-devel <xen-devel@lists.xenproject.org>, Keir Fraser <keir@xen.org>
List-Id: xen-devel@lists.xenproject.org

On 05/11/13 10:58, Jan Beulich wrote:
>>>> On 04.11.13 at 19:54, Andrew Cooper <andrew.cooper3@citrix.com> wrote:
>> --- a/xen/arch/x86/acpi/boot.c
>> +++ b/xen/arch/x86/acpi/boot.c
>> @@ -289,6 +289,17 @@ static int __init acpi_parse_hpet(struct acpi_table_header *table)
>>  		return -1;
>>  	}
>>  
>> +	/*
>> +	 * Some BIOSes provide multiple HPET tables. Warn that we will ignore
>> +	 * them.
>> +	 */
>> +	if ( hpet_address )
>> +	{
>> +		printk(KERN_WARNING PREFIX
>> +		       "Found multiple HPET tables. Only using first\n");
>> +		return -1;
>> +	}
> If there really are examples of this, and if those HPETs work
> properly, perhaps we should rather make use of them?
>
> Jan
>

The cause of this was two HPET acpi tables appearing.  This got 'fixed'
by a BIOS update (after which there was only a single HPET table), but I
felt it was worth warning about.

It might be nice to support multiple hpets is such a system existed.  It
would however be another fairly large chunk of work and I do not believe
I have appropriate hardware to test any development work on.

~Andrew