Re: Flushing writes to PCI devices

Roland Dreier
2006-09-21T20:57:09Z

Bryan> Yes. If your device requires that writes to some locations
Bryan> in MMIO space be performed in a specific order, you must
Bryan> explicitly do this in your driver. Intel CPUs will flush
Bryan> posted writes out of order, for example.

Really? Just normal posted PCI writes without using MTRRs or
write-combining or anything like that?

That doesn't seem right to me, and I would expect all sorts of things
to break if it were true.

- R.