Re: newbus IO ordering semantics - moving forward

On 10/27/2011 1:28 PM, Adrian Chadd wrote:
* Make the bus default to use ordered semantics, much like what Linux
does - ie, all IO read/writes (io or memory) are in-order and flushed
with a barrier;
* Add an option which allows the driver to request a region with
loose-running/lazy semantics, what we're supposed to have now, and
then leave barriers up to the driver;
* Print out something nice and loud if a driver decides to use the
lazy/loose semantics, which may result in unpredictable behaviour on
non-{i386,amd64}.

I'd appreciate some feedback/comments before I go off and code all of this up.



No. Please don't change the current semantics which are well understood if only fitfully adhered to. This would put us in the position of having some drivers possibly work slower because they didn't do the "lazy" request.

I also am not sure I agree with your characterization of linux semantics.
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