On Tue, 1 Jun 2010, Rafael J. Wysocki wrote:
> > Therefore the default state for unbound PCI devices should be
> > runtime-PM-enabled.
>
> Why do you think it should?
So that they can be put into a low-power state. If they are disabled
for runtime PM then they will remain in a high-power state.
> > Something like the patch below, awkward though it is. Does this look
> > reasonable?
>
> I'm not sure if r8169 and e1000e will work with it. Probably not, but I'm
> too tired to check right now. :-)
You mean because they already include their own runtime power
management? Then they would need to be updated to match these changes,
naturally.
> > @@ -365,15 +380,24 @@ static int pci_device_probe(struct devic
> >
> > static int pci_device_remove(struct device * dev)
> > {
> > + struct device_driver *driver = dev->driver;
> > struct pci_dev * pci_dev = to_pci_dev(dev);
> > struct pci_driver * drv = pci_dev->driver;
> >
> > if (drv) {
> > - if (drv->remove)
> > + if (drv->remove) {
> > + pm_runtime_get_sync(dev);
> > drv->remove(pci_dev);
> > + pm_runtime_put_noidle(dev);
> > + }
> > pci_dev->driver = NULL;
> > }
>
> Is "else" missing here or am I missing something?
I don't think an "else" is missing. Rather, the entire "if (drv)"
line should be eliminated because it can never fail.
> > + /* Undo the pm_runtime_get_sync() in local_pci_probe() */
> > + dev->driver = NULL;
> > + pm_runtime_put_sync(dev);
> > + dev->driver = driver;
> > +
> > /*
> > * If the device is still on, set the power state as "unknown",
> > * since it might change by the next time we load the driver.
>
> Do PCI bus type callbacks need to be reworked to work correctly with unbound
> devices?
They do; I neglected to take care of them when first writing this
patch. After everything is working I'll submit it for real. For now,
the point was to find out whether this is going in the right direction.
Alan Stern
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