[OpenBIOS] [PATCH] pci: fix BAR setup

[Artyom Tarasenko]

On Mon, May 14, 2012 at 3:07 PM, Mark Cave-Ayland
<mark.cave-ayland at ilande.co.uk> wrote:
> On 12/05/12 10:11, Blue Swirl wrote:
>
>>> Agreed. On current SPARC, the only non-zero Range on PCI is for 64-bit
>>> memory. For the memory ranges we see:
>>>
>>> 0200.0000 0000.0000 0000.0000 8000.8090 0000.0000 0000.0007 0000.0000
>>> 0300.0000 0000.0001 0000.0000 8000.8091 0000.0000 0000.0007 0000.0000
>>>
>>> My recollection is that memory space PCI RA (real address rather than
>>> physical address, because now we're behind a hypervisor) ranges from
>>> 8000.8090.0000.0000 through 8000.8097.FFFF.FFFF - which would match your
>>> guess that the parent_base needs to be hacked if 0800.0000 is going to be
>>> the BAR and is going to represent 1ff.0800.0000.
>>>
>>> So, why does OpenBios have 0100.0000 as a child base in the first place?
>>
>>
>> It's to avoid VGA legacy mapping at 0xa0000. If I change
>> hwdefs.pci.pci_mem_base in arch/sparc64/openbios.c to 0, OpenBIOS will
>> crash during VGA init. Previously this worked because the PCI devices
>> were mapped somewhat randomly and by chance, VGA legacy low mem area
>> was avoided.
>>
>> I think the correct fix is to make QEMU VGA device disable the legacy
>> mapping unless explicitly enabled. Alternatively the child base
>> arithmetic could be fixed in OpenBIOS like proposed by Jakub.
>
>
> Did a patch ever come out of this discussion in the end?
>

No. :-) Feel free to fix it, unless Blue prefers fixing it himself...

-- 
Regards,
Artyom Tarasenko

solaris/sparc under qemu blog: http://tyom.blogspot.com/search/label/qemu