graphics on G4

[Justin Hibbits]

On Thu, Oct 23, 2008 at 04:04:22AM +1000, Peter Grehan wrote:
> Hi Nathan,
> 
> >One thing that worries me about our PMAP layer could cause
> >this. This machine has a lot of RAM. What happens if we have
> >physical or device memory in the same range as kmem VAs?
> >It seems like trying to modify it through the BAT map (as
> >zero/copy page, /dev/mem and friends do) will overwrite
> >random bits of KVA instead...
> 
>  Apple h/w seems to use 0-2G for RAM, and 2G and up for MMIO.
> G5's can then use > 4G for additional RAM. I've not seen a
> system that has a conflict with the 2 seg's used for KVA, but
> I wouldn't say it's not possible.
>  
>  Justin - can you drop into OFW, do a 'dev screen' and
> '.properties', and list the 'address' property ?
> 
> later,
> 
> Peter.

The address property is a0008000, from ofw.  This seems like a rather odd
address, being 8 pages inside the 2.5GB memory space.

- Justin