Re: Dualboot Mac OS X and NetBSD on Power Mac?

[Michael <macallan%netbsd.org@localhost>]

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Hello,

On Apr 27, 2010, at 9:39 PM, Chris Ross wrote:

> On Apr 27, 2010, at 20:21, Michael wrote:
> > Actually it gets much further - it hangs when enabling the MMU and  
> > so far I couldn't figure out why. Also, there's conflicting  
> > information out there about BATs being emulated in bridge mode  
> > ( most docs say nothing or no yet OpenBSD happily uses them anyway )
> > Also, there is no support for the PCIe bridge in last generation G5s.
>
>  Right.  And, I have a last-gen G5, so I'd need the PCIe bridge  
> support too.  One more strike against me even considering this, I'm  
> afraid.

I have the datasheet, writing a simple driver for the bridge that's  
good enough for bridge mode is simple enough ( for 64bit mode we'd  
need to use the built-in IOMMU or DMA would be confined to the lower  
2GB of RAM which are visible to the PCI bus ). But for that I'd have  
to get the MMU enabled first. Guess I need to read some more freebsd  
code.

> > You can compile a 32bit G5 kernel ( or at lease I could not too  
> > long ago ) - they don't reach userland however. 'Real' 64bit kernel  
> > hit an #error elsewhere, somewhere in OF support IIRC. Otherwise,  
> > we have a more or less generic SATA driver, no clue if that's  
> > enough for the G5.
>
>  I'd be happy to try running a 32-bit (or 64-bit "careful", or  
> whatever else) to test on my last-gen G5, but without the PCIe  
> bridge support, I'm sure it wouldn't get very far.

Yeah, you wouldn't get any actual device drivers attached.

>  If anyone wants me to try, and report back, let me know.  I only  
> have the one G5 machine, which is also my primary [Mac OS X]  
> desktop, so I don't know that I can be of any real dev help, even  
> *if* I thought my skills were adequate.  :-)

Well, I have a PCIe G5 which I've been hacking on every now and then -  
if I find out what I'm missing with the MMU the rest is not all that  
difficult.

>  Thanks for all the information, and I hope to spur someone into  
> getting more last-gen G5 Mac support working.  Happy to help where I  
> can, but as noted, don't know that there's too much I can do/try.

I need someone with better powerpc-fu than myself. The rest of the  
hardware isn't all that different, I'm sure I can get that going.

>  Anyone willing to work hard-core on it, I could likely be convinced  
> to buy a last-gen G5 from eBay to contribute.  Can't cost that much  
> any more, eh?

They're fairly cheap these days, I think I saw a dual 2GHz one for  
about $300 not too long ago. Probably has something to do with apple  
dropping powerpc support in 10.6

have fun
Michael

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