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

[Andreas Färber]

Am 20.12.2009 um 19:01 schrieb 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.

ATI used to sell special "Mac Edition" graphics cards. That would seem  
to back up the possibility of a ppc VGABIOS on Mac.

Never tried putting such a card into a PC though or vice versa. Maybe  
we'd get the same sick-coloured penguins then...? ;)

Andreas

> 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.