[PATCH] PCI Hotplug: add address file and fix acpiphp bugs

[PATCH] PCI Hotplug: add address file and fix acpiphp bugs

This is the pending patch that adds 'address' file to show
PCI-address and a few other minor fixes.
As 2.6.0 is out, I'm resending the patch.
Would you mind taking this?

> > > Thanks.  I had a little time to try your patch today.  Sorry
> > > to report that it isn't working for me.
> > >
> > > I first powered off (successfully the 1st time) a populated slot
> > > and removed and reinserted the card into the same slot.  The slot
> > > powered back up but I was then unable to power it off.  I believe
> > > the following instruction that still exists in power_off_slot()
> > > may be preventing the slot from being powered off more than once.
> > >     func->flags &= (~FUNC_EXISTS);
> > >
> > > I then tried to insert an adapter in an un-populated slot.  For
> > > some reason (which I don't understand yet) there was an enabling
> > > error which I believe caused enable_device() to exit via a path
> > > that bypassed the instruction that sets the FUNC_EXISTS flag.
> > > I was then unable to power off the slot which I believe was due
> > > to the FUNC_EXISTS flag not being set.
> > >
> > > I didn't have time to definitely confirmed the above theories.
> > > I'll take a closer look at this tomorrow unless you are able
> > > to diagnose using my vague clues :)
> >
> > It turns out that both of the above mentioned problems happened
> > because the call to acpiphp_configure_slot() from enable_device()
> > failed after inserting the card.  When this happens enable_device()
> > exits without setting the FUNC_EXISTS flag for any of the slot
> > functions.  Subsequent attempts to power off the same slot fail
> > when power_off_slot() is unable to locate a function with both
> > FUNC_HAS_EJ0 and FUNC_EXISTS flags set.
> >
> > The patch works okay when using a card that allows
> > acpiphp_configure_slot() to succeed but I believe it should
> > be improved to allow the slot to be powered off following
> > device enablement errors.
>
> Thanks for testing and comments.
> I really appreciate it.
>
> This problem turned out to be somewhat fragile state
> transition:
>
> a lifecycle of a slot is (if there's no error)
>
>   function             state
> ----------------------------------------------------
> 0                      nothing
> 1  power_on_slot()  -> SLOT_POWERDON
> 2  enable_device()  -> SLOT_POWEREDON + SLOT_ENABLED
> 3  disable_device() -> SLOT_POWEREDON
> 4  power_off_slot() -> nothing
>
> but if any error occur during enable_device(), slot will remain
> SLOT_POWERDON, but some functions on the card may not have
> FUNC_EXISTS flags, which will eventually prevents powering
> off in power_off_slot(), state transition from 1 to 4 directly.
> I.e, the FUNC_EXISTS flag introduced more states to
> complicate things.
>
> The FUNC_EXISTS flag was introduced after some discussion
> between me and Irene Zubarev, but it has no more meaning
> than that the function has corresponding 'pci_dev' structure.
> So I eliminated the usage of FUNC_EXISTS and the result is
> the patches attached to this mail (for both 2.4 and 2.6.
> I think Greg already applied the 2.4 'cleanup' patch to his tree,
> but it's not in Marcelo's release so I'm re-attaching to
> this mail for anyone interested in this topic.  It's identical
> to the one I posted earlier).
> These patches don't include Gary's patch in his post last week,
> so please apply separately.
>
> Please note that current acpiphp driver cannot handle a
> PCI card that has a PCI-to-PCI bridge on it (support
> for such cards is incomplete).  But if it's treated as
> an error, it should be recoverable anyway.