Re: [linux-pm] PCI hotplug v.s. suspend

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On Mon, 15 Jun 2009, Alan Jenkins wrote:

> Alan Stern wrote:
> > On Mon, 15 Jun 2009, Alan Jenkins wrote:
> >
> >   
> >> Hi,
> >>
> >> I triggered a WARNING while hacking on eeepc-laptop's 
> >> rfkill-by-pci-hotplug.  I saw "Trying to free already-free IRQ" in 
> >> ath5k_pci_remove(), because the IRQ was already freed by 
> >> ath5k_pci_suspend().  My changes to eeepc-laptop had allowed the PCI 
> >> device to be removed while suspended.
> >>
> >> Are PCI drivers supposed to handle remove() while suspended?
> >>     
> >
> > Yes.  You found a bug in the driver.  However it's not clear (to me at
> > least) whether the bug is that the IRQ is freed in the suspend method
> > or that there's no check for already-freed in the remove method.  My 
> > guess is the latter.
> >
> > Alan Stern
> >   
> 
> The example in Documentation/power/pci.txt shows free_irq() being called
> in suspend (and request_irq() in resume).  So the problem is in remove().

I'm not sure whether the example is trustworthy.  There was some
discussion quite a while ago regarding whether drivers should free
their IRQs during suspend, but I don't remember what the outcome was.

Alan Stern

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