graphics on G4

[Peter Grehan]

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.