Re: [PATCH v3 01/10] PCI: Keep pci_fixup_irqs() around after init

[Thierry Reding <thierry.reding-RM9K5IK7kjKj5M59NBduVrNAH6kLmebB@public.gmane.org>]

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On Fri, Sep 07, 2012 at 10:19:46AM -0600, Stephen Warren wrote:
> On 08/15/2012 01:42 PM, Bjorn Helgaas wrote:
> > On Wed, Aug 15, 2012 at 1:28 PM, Thierry Reding
> > <thierry.reding-RM9K5IK7kjKj5M59NBduVrNAH6kLmebB@public.gmane.org> wrote:
> >> On Wed, Aug 15, 2012 at 10:06:27AM -0700, Bjorn Helgaas wrote:
> >>> On Thu, Jul 26, 2012 at 12:55 PM, Thierry Reding
> >>> <thierry.reding-RM9K5IK7kjKj5M59NBduVrNAH6kLmebB@public.gmane.org> wrote:
> >>>> When using deferred driver probing, PCI host controller drivers may
> >>>> actually require this function after the init stage.
> >>>>
> >>>> Signed-off-by: Thierry Reding <thierry.reding-RM9K5IK7kjKj5M59NBduVrNAH6kLmebB@public.gmane.org>
> >>>> ---
> >>>> Changes in v3:
> >>>> - none
> >>>>
> >>>> Changes in v2:
> >>>> - use __devinit annotations
> >>>
> >>> Your original patch removed __init completely.  Here you change it to
> >>> __devinit.  That means we decide whether to discard the function based
> >>> on whether CONFIG_HOTPLUG is supported.  But I think your point is not
> >>> about hotplug; it's merely that we should be able to scan a PCI bus
> >>> after init-time.  We ought to be able to do a late PCI scan even if
> >>> hotplug is not supported.
> >>>
> >>> Therefore, I'd be inclined to remove __init completely unless you have
> >>> another reason for preferring __devinit.
> >>
> >> I thought __devinit would resolve to nothing if HOTPLUG is defined and
> >> __init otherwise. That seemed more appropriate. However you are right
> >> that it is useful to always have it available, so I'm fine with removing
> >> the annotations altogether. Do you want me to follow up with a patch? Or
> >> can you just take the first version? I'm not sure if it still applies.
> > 
> > You're right about how __devinit works.  It's just that I don't think
> > hotplug is actually relevant here.  We're trying to make
> > pci_fixup_irqs() work after init, whether it's because of hotplug or
> > simply because the arch scans host bridges after init.
> > 
> > I applied this to my "next" branch.  Thanks!
> 
> Bjorn, I don't see this patch in next-20120907. Did it get dropped for
> some reason?

Yes, it turns out that dropping the annotations causes lots of section
mismatches on other architectures. See here[0] for the details. I think
the solution to the issue would be to either remove HOTPLUG altogether
and drop __devinit and __devexit annotations or update all architectures
to fix these warnings. I think Bjorn and I settled on the latter because
it's obviously less intrusive. I've been busy building toolchains for
all the PCI architectures and I think I have all of them. I'll just need
some more time to build, find and fix any remaining section mismatches.

Thierry

[0]: http://www.linux-mips.org/archives/linux-mips/2012-08/msg00250.html

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