Re: [Bug 9528] x86: Increase PCIBIOS_MIN_IO to 0x1500 to fix nForce 4 suspend-to-RAM

["Yinghai Lu" <yhlu.kernel@gmail.com>]

On Dec 23, 2007 9:53 AM, Linus Torvalds <torvalds@linux-foundation.org> wrote:
>
>
> On Sun, 23 Dec 2007, Carlos Corbacho wrote:
> >
> > Fix suspend-to-RAM on nForce 4 (CK804) boards by increasing
> > PCIBIOS_MIN_IO.
> >
> > Fixes kernel bugzilla #9528
> >
> > Problem:
> >
> > Linus' patch (52ade9b3b97fd3bea42842a056fe0786c28d0555) to re-order
> > suspend (and fix fall out from Rafael's earlier suspend reordering work)
> > broke suspend-to-RAM on nForce 4 (CK804) boards.
> >
> > Why:
> >
> > After debugging _PTS() in the DSDT, it turns out these nVidia boards are
> > trying to write to an IO port > 0x1000 (0x142E) during suspend. Before the
> > re-ordering, we got away with this.
>
> Very interesting.
>
> HOWEVER.
>
> I'd much rather figure out what the magic IO resource is that clashes.
>
> It's almost certainly some hidden and undocumented (or badly documented)
> ACPI IO area that the kernel doesn't know about, because it's not a
> regular PCI BAR resource, but some northbridge (or southbridge) magic
> register range.
>
> Those ranges *should* be reserved by the BIOS in the ACPI tables, but this
> would definitely not be the first time that doesn't happen.
>
> But the right fix would be for us to just figure out what the range is ass
> a PCI quirk, and just know to avoid it on purpose, ratehr than just being
> lucky and happen to avoid it because PCIBIOS_MIN_IO just happens to be
> bigger than the particular address.
>
> So can you:
>  - show what your /proc/ioports contains (*with* the bug triggering, ie
>    non-working suspend, so we see what it is that actually ends up using
>    that area)
>  - send out 'dmesg' for a boot (same deal)
>  - add "lspci -xxxvv" output to the deal too.
>
it looks like BIOS doesn't assign io port in bus 0. ( for PMU? or some 00:01.1)
and kernel try to assign value to it according to PCIBIOS_MIN_IO.

sometime some systems could have several HT chains.
bus: [00,08] on node 0 link 1
bus: 00 index 0 io port: [5000, dfff]
bus: 00 index 1 io port: [e000, efff]
bus: 00 index 2 io port: [0, fff]
bus: 00 index 3 mmio: [de000000, dfffffff]
bus: 00 index 4 mmio: [e0000000, e7ffffff]
bus: 00 index 5 mmio: [a0000, bffff]
bus: 00 index 6 mmio: [f0000000, ffffffff]
bus: [80,86] on node 1 link 2
bus: 80 index 0 io port: [1000, 4fff]
bus: 80 index 1 io port: [f000, ffff]
bus: 80 index 2 mmio: [c0000000, ddffffff]
bus: 80 index 3 mmio: [e8000000, efffffff]

current all the buses will use ioport_resource

@@ -1158,6 +1162,8 @@ struct pci_bus * pci_create_bus(struct d
        b->resource[0] = &ioport_resource;
        b->resource[1] = &iomem_resource;

kernel could try to allocate resource from [0x1000, 0x4fff] for the
device in first HT chain...
..
I met one case: when some cards insert, i can not use mcp55 on die nic.
then i make one patch that could read KB northbridge pci conf space to
make different peer root bus has right io/iomem resource range.
pci_assign_resource could get right value for the devices that is not
assigned io value by BIOS.

YH