[SeaBIOS] Graphics card pass-through working with two pass pci-initialization

André Weidemann Andre.Weidemann at web.de
Sun May 29 21:30:30 CEST 2011


On 29.05.2011 17:22, Jan Kiszka wrote:
> On 2010-05-28 20:49, André Weidemann wrote:
>> Hi,
>> On 28.05.2011 10:18, Jan Kiszka wrote:
>>> On 2011-05-26 23:19, André Weidemann wrote:
>>>> On 27.05.2011 21:50, André Weidemann wrote:
>>>>> On 27.05.2011 21:40, André Weidemann wrote:
>>>>>> If I am not mistaken then the graphics card needs 2 bars, one with
>>>>>> 256MB
>>>>>> and one with 128K. The sound card then needs 1 bar with 16K of PCI
>>>>>> memory.
>>>>>> How big is the PCI memory with seabios?
>>>>>> Is there really not enough space to "squeeze" in those extra 16K?
>>>>> I obviously forgot to add up the other memory that is used...
>>>>> 32MB go to the standard VGA card. Running qemu-kvm with "-vga none" did
>>>>> not work, so I left it in. And the e1000 NIC needs another 128K.
>>>>> I'll see if I can get rid of the standard VGA card. I guess that should
>>>>> free enough memory for the sound card.
>>>> I did some more testing by starting the VM with the paramter "-vga none"
>>>> and passed both the VGA card and the sound card to it. With this option
>>>> the VM did not boot,
>>> Where did it hang, ie. what IP was reported by info cpus?
>> I added some debug options and found out, that the VM hangs when trying
>> to initialize the graphics card ROM.
>> See here:
>> http://pastebin.com/S9a8uQfU
>> And some additional info here:
>> http://pastebin.com/AC4rw8Ek (info cpus/registers)
>> http://pastebin.com/yYkn8jL2 (info pci)
> Yeah, you definitely run out of PCI memory.
> Plus you may suffer from the PAM/SMRAM bug I wrote about in the wiki.
> Try if this hack improves the situation:
> http://git.kiszka.org/?p=qemu-kvm.git;a=commitdiff;h=96e600f43275310364c0310519d6ab6540bb7d25

I applied above patch, but it did not make a difference. The VM did not 
boot with the parameter "-vga none".

I found the time to apply your two patches here:
After doing so, Gerds q35 bios branch prints an error message during 
The error comes from line 33 here:
How do I adjust the memory area here?


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