Re: [Xen-devel] [RFC 2/8] x86/acpi: Warn about multiple HPET tables

[Andrew Cooper <andrew.cooper3@xxxxxxxxxx>]

On 05/11/13 10:58, Jan Beulich wrote:
>>>> On 04.11.13 at 19:54, Andrew Cooper <andrew.cooper3@xxxxxxxxxx> 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

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