About "acpi0: reservation of ... failed" message in `dmesg`

[John Baldwin]

Nate Lawson wrote:
> avatar Lin wrote:
>>   Our customers are concerned about the following messages in `dmesg` output.
>>
>> ===
>> acpi0: reservation of 0, a0000 (3) failed
>> acpi0: reservation of 100000, bff00000 (3) failed
>> ===
>>
>>   Please help to clarify this issue.
>>
>>   Or , in other direction, where to find official document to convince
>> our customers that these messages are ignorable ?
> 
> It is related to the sysresource acpi memory objects. It means that
> something was using the system resource before acpi allocated it. For
> #1, that looks like lowmem up to the VGA range. For #2, it looks like
> option ROMs.
> 
> The BIOS has configured the devices beforehand so as long as everything
> works, the msgs can be ignored.

Actually, to handle non-ACPI systems and ACPI systems that do not list 
system memory in the system resource objects, I added a 'ram0' device 
which uses the SMAP table and allocates address space for all of memory 
to perform a similar function to ACPI system resource objects.  Often 
this message triggers now because the ram0 device has claimed the 
resources before ACPI gets a chance.  You can certainly ignore these 
messages.  If you look in 'devinfo -ur' you will probably find that 
these resource ranges are allocated by the ram0 device.

-- 
John Baldwin