Write combining for PowerPC processors?

[Kendall Bennett]

Benjamin Herrenschmidt <benh at kernel.crashing.org> wrote:

> > Would mprotect() also support enabling write combining on PPC systems? 
> > Does X.org doe something similar to the MTRR stuff on PPC systems or is 
> > it supposed to be entirely up to the kernel.
> 
> I told you that there is no CPU based write combining thing. Or rather,
> the CPU itself doesn't care. It has to be dealt at the northbridge
> level, and so is far from what mprotect() can do. PPCs have no MTRR
> neither. So you'll have to look at your northbridge documentation and
> see if you can do something like write combining.

Cool. I think Michal found the control registers that will do what we 
want, so we will tinker with it and see what happens ;-)

Regards,

---
Kendall Bennett
Chief Executive Officer
SciTech Software, Inc.
Phone: (530) 894 8400
http://www.scitechsoft.com

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