[OpenBIOS] [PATCH] pci: fix BAR setup

[Artyom Tarasenko]

On Mon, May 14, 2012 at 8:58 PM, Blue Swirl <blauwirbel at gmail.com> wrote:
> On Mon, May 14, 2012 at 1:49 PM, Mark Cave-Ayland
> <mark.cave-ayland at ilande.co.uk> wrote:
>> On 14/05/12 14:28, Artyom Tarasenko wrote:
>>
>>>>> 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...
>>
>>
>> I'm not sure I'm confident enough with PCI to do this, and I'm also not sure
>> what Blue's recommended fix actually is? Is it to increase parent_base by
>> 0x1000 or set child_base to zero?
>
> The best solution is to fix VGA (assuming my analysis was right) and
> set child_base to zero.

Blue, do you know whether the QOMification improved the situation with
the legacy VGA low mem area?


--
Regards,
Artyom Tarasenko

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