Re: Please revert 5adc55da4a7758021bcc374904b0f8b076508a11 (PCI_MULTITHREAD_PROBE)

[david@lang.hm]

On Wed, 9 May 2007, Cornelia Huck wrote:

> On Wed, 9 May 2007 10:09:33 -0700 (PDT),
> david@lang.hm wrote:
>
> > > Hm, so that sound like a case for a distinct setup() routine:
> > >
> > > 1. bus calls ->probe(), which return synchronously
> > > 2. bus calls ->probe_async() for all devices (optional)
> > > 3. bus waits for all probes to finish
> > > 4. bus calls ->setup() for all devices (which does the registering)
> >
> > this is exactly what I've been trying to describe.
>
> Nearly, but with a slightly different spin...
>
> > > (->setup() can but need not be sync, although it should be for your
> > > case)
> >
> > if it's not sync then you have race conditions again
>
> ...but not all busses will care. If your bus wants to enforce ordering,
> it must enforce it to be sync. If your bus allows hotplug and calling
> setup() later on, it may also allow async. (setup() is a bit
> dual-purpose in this idea.)

if you want the registration to use hotplug and be async then do do the 
registration during step 2 and make step 4 be a noop, in fact some drivers 
may do all their work in step 2, while others (everything currently) will 
do all their work during step 1

David Lang


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