On Fri, May 29, 2009 at 18:18, David Miller wrote:

From: Mike Frysinger <redacted>

quoted

the difference is that one of these is required in order for anything
to get done and the other is always useless noise.  also, the Blackfin
core does do speculative data fetching on external memory, but not
MMRs, so the stalling due to the data cache line fills will be
mitigated unlike the useless MMR reads.

You only need to read the register if the descriptor status is not
ready yet, and you're just spinning in that case anyways.

I doubt it makes any real difference if implemented properly.

But I guess it's more fun to speculate than to actually try it out.
:-/

and i guess it's more fun to waste time attempting to support an
operating mode that the hardware has never and most likely will never
support
-mike