Post by Colin Hankins
That is disappointing. I thought it would come in usefull, from the host
system point of view, to send one message simultaneously (since the Vendor
Defined Messages allows for broadcast type routing) from the the host to
multiple cards in the PCI-E fabric. Yes, I can accomplish the same thing
with individual writes to each board, but one message would have been much
cooler and less bandwidth.
It's more complicated than that. Remember that the processor doesn't
really speak PCIExpress directly. There is a translation, in the south
bridge. To do anything other than PCI-type transactions, you have to talk
directly to the root complex. There are multiple roots in the typical PC,
and there's no standard method for addressing them, so whatever you did
would only work on a few architectures.
The sad fact is that anything in PCIExpress that is not PCI-compatible is
never going to get widespread adoption. That includes isochronous and
Tim Roberts, ***@probo.com
Providenza & Boekelheide, Inc.