[LinuxBIOS] Opteron caching of device memory

[ron minnich]

On 6/14/07, Marc Jones <Marc.Jones at amd.com> wrote:

> Now that I think about it, it makes sense that you can't set writeback
> to noncoherent (nonsystem) memory space. What if another device wants to
> write to that memory. There is no way for the cache to snoop that it was
> written. You would need a coherent HT link to to your FPGA to get the
> cache snoop messaging.

Also, writeback would be a disaster for drivers. The expectation for a
driver is that when the code sets bist in an MMIO space, that bit gets
set. That's a writethrough semantic.

thanks

ron