Re: [PATCH] fsldma: use PCI Read Multiple command

Kumar Gala
2009-04-27T20:04:29Z

On Apr 27, 2009, at 3:00 PM, David Hawkins wrote:

>
>>> Can you give me an example of non-PCI memory that would be
>>> non-prefetchable that you'd like us to try? We can see if our
>>> host CPUs have an area like that ... we just need to know
>>> what device to look for first :)
>> You can mark the pci inbound window on the 83xx as non-prefetchable
>> (assuming 83xx is host). On a x86 host I doubt there is any easy
>> way to get non-prefetchable memory.
>
> Yep, we were going to do that, but chose to use the
> 1MB region already setup for the IMMRs since its already
> marked as non-prefetchable. We were only doing reads, so
> it wasn't going to hurt anything.
>
> I doubt that marking one of the other BAR regions
> as non-prefetchable will give a different result.
> However, we're more than happy to double-check if
> you'd like.

Its possible you'll get a different result since IMMR is a register
space internal and thats normally a completely different bus than
memory would be (internal to the 83xx). I'd suggest double-checking w/
a BAR marked non-prefetch pointing to real memory.

- k