Re: [PATCH v3] PCI: Only enable IO window if supported

[Guenter Roeck]

On 08/05/2015 06:38 PM, Yinghai Lu wrote:
> On Wed, Aug 5, 2015 at 6:14 PM, Yinghai Lu <yinghai@xxxxxxxxxx> wrote:
> > It only can avoid warning with bridge, and still have warning on
> > devices under the bridge.
> >
> > also would have problem on transparent bridges, like
> >
> > BRIDGE_A ---- BRIDGE_AA----DEVICE_AA
> >                     |
> >                     \-- BRIDGE_AB ---DEVICE_AB
> >
> > if only BRIDGE_A and BRIDGE_AA are transparent, and BRIDGE_AB is not.
> >
> > and if pci_bridge_supports_io() return false for BRIDGE_A.
> >
> > We will have all three bridges have PCI_BUS_FLAGS_SUPPORTS_IO cleared.
> > so all will not been sized and will not get assigned io port resource.
> >
> > later DEVICE_AA could root bus io port as parent, and get io resource assigned.
> > but DEVICE_AB will not get assigned.
> >
> > so we should get rid of pci_bridge_supports_io(), and just check root
> > resource IO port.
>
> I would suggest this version instead:
>
> Subject: [PATCH] PCI: Only try to assign io port only if root bus support that

Bjorn had asked me to move the IO support check out of pci_bridge_check_ranges().
It looks like you want to keep it there.

Can you explain your reasons ? Sorry, I just don't understand.

Guenter

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