Re: [patch] drivers: wait for threaded probes between initcall levels

Kyle Moffett
2006-10-30T18:50:17Z

On Oct 30, 2006, at 09:42:59, Matthew Wilcox wrote:
> On Mon, Oct 30, 2006 at 09:23:10AM -0500, Kyle Moffett wrote:
>> recursive make invocations and nested directories). Likewise in
>> the context of recursively nested busses and devices; multiple PCI
>> domains, USB, Firewire, etc.
>
> I don't think you know what a PCI domain is ...

Fair enough, I guess I don't, really...

>> Well, perhaps it does. If I have (hypothetically) a 64-way system
>> with several PCI domains, I should be able to not only start
>> scanning each PCI domain individually, but once each domain has
>> been scanned it should be able to launch multiple probing threads,
>> one for each device on the PCI bus. That is, assuming that I have
>> properly set up my udev to statically name devices.
>
> There's still one spinlock that protects *all* accesses to PCI
> config space. Maybe we should make it one per PCI root bridge or
> something, but even that wouldn't help some architectures.

Well, yes, but it would help some architectures. It would seem
rather stupid to build a hardware limitation into a 64+ cpu system
such that it cannot initialize or reconfigure multiple pieces of
hardware at once. It also would help for more "mundane" systems such
as my "Quad" G5 desktop which takes an appreciable time to probe all
the various PCI, USB, SATA, and Firewire devices in the system.

Cheers,
Kyle Moffett