No. Vendor-defined messages are a more-or-less useless part of the spec,
designed for things like bus extenders where the two ends need to
communicate with each other.
There's really no problem you can't solve using normal cycles.
--
Tim Roberts, ti...@probo.com
Providenza & Boekelheide, Inc.
Thanks for the reply.
"Tim Roberts" <ti...@probo.com> wrote in message
news:dnsrm355do39k0po9...@4ax.com...
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
virtual channels.
Would you happen to know of any "high-end" systems that incorpoate root
complex chipsets that support full PCI-E specification (if there is such a
device)?
Again, thanks for the replies.
"Tim Roberts" <ti...@probo.com> wrote in message
news:avq0n316gm6tfjlek...@4ax.com...
There aren't very many chipset makers. It shouldn't be too hard to check
them.
However, again I ask: what's the point? Your code is only going to work on
that chipset, and possibly even one version of that chipset. And, in the
end, you're talking about an utter micro-optimization. You're going to
invest days of effort in chasing down the mechanism and the possible
applicable chipsets, for the sake of saving a handful of nanoseconds.
It just doesn't make sense to me.