Re: [PATCH] Make hot unplugging of PCI buses work

Linus Torvalds (torvalds@transmeta.com)
Sun, 23 Feb 2003 16:59:03 -0800 (PST)


On Sun, 23 Feb 2003, Russell King wrote:
>
> However, whether x86 PCs will survive bus renumbering or not remains to
> be seen. We currently try to leave as much of the configuration intact
> from the BIOS.

Note that I made cardbus bus numbering _ignore_ the BIOS-setup numbering
even on PC's, exactly because of issues like this - trying to keep the
original BIOS numbering just won't work if the BIOS sets the wrong numbers
(I saw a BIOS that had happily assigned the _same_ PCI bus number to both
cardbus functions, whee).

I think we can (and should) make all hotpluggable PCI bridges use that
same cardbus logic.

The real problematic case I see is if there are transparent hotplug
bridges, with some devices just magically appear and disappear from a part
of a bus because of some invisible bridge. I don't know if such things
exist or even _can_ exist, but the perverse nature of PC hardware makes me
suspect they do.

Linus

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