Re: pci-disable-decode-of-io-memory-during-bar-sizing.patch

Linus Torvalds
2007-10-30T22:23:13Z

On Tue, 30 Oct 2007, Jesse Barnes wrote:
>
> The per-device flag is fine with me, but I should make something clear:
>
> MMCONFIG IS NOT BROKEN!

Trust me, it is.

The particular problem _you_ had with it is only a small small part of the
bugs we have had.

> What's broken is our PCI probing with certain address space layouts that
> include MMCONFIG space.

No. You really don't see the big picture. There's been tons of problems
with MMCONFIG. Like the fact that other devices have their IO regions
registered on top of it, because the MMCONFIG thing was done as a hidden
resource. Or the fact that the area claimed was too small. Or too large.
Or not listed at all.

The whole thing is a total disaster. I told Intel engineers literally
*years* ago to not do that idiotic "hidden IO resources that are described
by firmware that then inevitably gets things wrong", and yet what happens?
Every single time.

Linus