Re: [Qemu-devel] [PATCH 1/8] Support PCI based option rom loading

[Alexander Graf]

On 20.12.2009, at 18:55, Anthony Liguori wrote:

> Alexander Graf wrote:
>> Don't macs usually have a powerpc vgabios?
>>  
> I'm not certain, but this is what x86emu is for in X11.
> 
> VGA is a PC concept and just about nothing about it really make sense on a 
> different architecture.  The interface is an extension of the PC BIOS 
> (software interrupts) and the dictated memory layouts are specific to the 
> x86.  I think most non-x86 systems have to use native drivers for whatever 
> graphics cards they support from the start.

Yes. The Alpha for example used stock VGABIOSes. IIRC Sparc has its own 
graphics anyways and I don't know about the others, but I suspect they either 
use x86 VGABIOSes or no VGABIOSes.

Macs are different though. IIRC they have a normal VGA interface in ppc logic, 
but I might be wrong. Maybe it's also some OpenFirmware stuff. They definitely 
don't have an x86 VGABIOS in the graphics card's rom slot, but something 
different.

Since we're using the Cirrus on Macs, I guess we'd need a Cirrus PPC VGABIOS - 
phew.

Other PPCs on the other hand, such as the Powerstation, use x86 roms.

Oh well, let's just export the x86 one for now but use video.x for video 
output. Looks like there'd be quite a lot of work involved in getting it 
aligned to real world mac hw :-(.

Alex

PS: Ben, please correct me if I'm wrong.