Re: [PATCH 2/3] PCI, ACPI: Don't glue ACPI dev with pci VFs

["Rafael J. Wysocki" <rjw@rjwysocki.net>]

On Wednesday, June 05, 2013 12:44:27 AM Rafael J. Wysocki wrote:
> On Friday, May 31, 2013 12:21:30 PM Jiang Liu wrote:
> > From: Yinghai Lu <yinghai@kernel.org>
> > 
> > When sriov is enabled, VF could just start after PF in pci tree.
> > like c1:00.0 will be PF, and c1:00.1 and after will be VF.
> > 
> > acpi do have dev with same ADR. that will make them get glued
> > wrongly.
> 
> How exactly are they glued in that case?
> 
> > Skip that if it is virtfn.
> 
> That should be a bit more specific as far as I can say.  I don't see why a VF
> would not have a valid ACPI device object corresponding to it.  Is there any
> particular reason?

To be precise, I don't quite see why it is impossible or invalid for a VF to
have a corresponding ACPI device object.  It may not be the case on this
particular system, but why not in general?

Rafael


> > Signed-off-by: Yinghai Lu <yinghai@kernel.org>
> > Signed-off-by: Jiang Liu <jiang.liu@huawei.com>
> > ---
> >  drivers/pci/pci-acpi.c | 4 ++++
> >  1 file changed, 4 insertions(+)
> > 
> > diff --git a/drivers/pci/pci-acpi.c b/drivers/pci/pci-acpi.c
> > index e4b1fb2..720f3a2 100644
> > --- a/drivers/pci/pci-acpi.c
> > +++ b/drivers/pci/pci-acpi.c
> > @@ -321,6 +321,10 @@ static int acpi_pci_find_device(struct device *dev, acpi_handle *handle)
> >  	u64	addr;
> >  
> >  	pci_dev = to_pci_dev(dev);
> > +	/* don't mix vf with real pci device */
> > +	if (pci_dev->is_virtfn)
> > +		return -ENODEV;
> > +
> >  	/* Please ref to ACPI spec for the syntax of _ADR */
> >  	addr = (PCI_SLOT(pci_dev->devfn) << 16) | PCI_FUNC(pci_dev->devfn);
> >  	*handle = acpi_get_child(DEVICE_ACPI_HANDLE(dev->parent), addr);
> > 
> 
-- 
I speak only for myself.
Rafael J. Wysocki, Intel Open Source Technology Center.