Re: PCI Express support for 2.4 kernel

Dan Hopper
2003-12-17T17:44:48Z

Linus Torvalds <torvalds@osdl.org> remarked:
>
> On Wed, 17 Dec 2003, Geert Uytterhoeven wrote:
> >
> > For the record: PCI Express is _not_ PCI-X.
>
> Ok, but "PCI Express" is too damn long to write, so we'll have to have
> _some_ sane name for it without typing for half an hour.

FWIW, "PCI-E" is in common use in these parts.

Also, wrt the config space backward compatibility issue, it is my
understanding that the PCI-E root complex and PCI-E devices can be
enumerated and used successfully with no software changes, within
the constraints of PCI. The BIOS or OS should be able to enumerate
devices, probe BARs and assign resources, perform basic error
handling, etc. without any PCI-E-specific changes.

The hardware is required to be able to initialize PCI-E links, set
things up to sane states, and so forth without software assistance
in order to make this magic happen. It would be interesting to hear
from Vladimir as to whether or not this is happening with his PCI-E
test system.

Having said all that, it's obviously preferable to end up with
native OS and BIOS support for the PCI-E extended configuration
space, extra error reporting mechanisms, etc. Native PCI-E devices
hanging off the bus somewhere might not work (or, at least, work
well) with an OS that doesn't grok the PCI-E extensions.

Dan