On Thursday 06 November 2014 16:08:57 Lucas Stach wrote:
> Am Dienstag, den 04.11.2014, 13:07 +0100 schrieb Arnd Bergmann:
> > On Tuesday 04 November 2014 12:00:52 Liviu Dudau wrote:
> > >
> > > While the description is potentially correct, what it fails to explain is
> > > that the
> > > choice of using the property or generating an unstable (across boots)
> > > unique
> > > number is actually the choice of the host bridge driver at the moment. I
> > > know that
> > > my earlier implementations were defaulting to the automatic numbering,
> > > but that has
> > > been dropped from the final series as Rob Herring was objecting to it.
> > >
> > > There is still scope to adopt a wide policy here, but for now it should
> > > say something
> > > to the tune:
> > >
> > > If present this property assigns a fixed PCI domain number to a host
> > > bridge,
> > > otherwise an unstable (across boots) unique number will be assigned.
> > > If you decide to use the property to assign a fixed PCI domain number
> > > to a host
> > > bridge you have to ensure that all the host bridge drivers present in
> > > the system
> > > follow the same policy. Otherwise, potentially conflicting domain
> > > numbers
> > > may be assigned to root busses behind different host bridges.
> >
> > But with the latest change to the domain handling, all drivers would
> > implement
> > this. I would just mention that Linux kernels older than 3.19 are probably
> > going to ignore this property.
> >
> Hm, I don't think we should stick those things into the binding docs, as
> those should not be Linux specific. IMHO the time when the parsing of a
> property gets implemented is a implementation detail that has nothing to
> do with the binding. Besides vendors always screw with this timeframes
> by doing backports.
Well, unlike most properties, this one is explicitly Linux-specific,
at least that is what the name implies.
Arnd
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