Re: [Bug 41722] Clevo M5X0JE hangs in ACPI init
From: Linus Torvalds
Date: Sun Jan 08 2012 - 17:23:51 EST
On Sun, Jan 8, 2012 at 2:13 PM, Rogério Brito <rbrito@xxxxxxxxxx> wrote:
>
> It doesn't boot with a vanilla kernel. It only boots when I pass the options
> above *and* compile the kernel with the following patch applied:
>
> ,----[ do_not_size_subtractive_decoding_transparent_pci_to_pci_bridges.patch ]
> | diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
> | index 86b69f85..84543f5 100644
> | --- a/drivers/pci/setup-bus.c
> | +++ b/drivers/pci/setup-bus.c
> | @@ -849,6 +849,10 @@ void __ref __pci_bus_size_bridges(struct pci_bus *bus,
> | break;
> |
> | case PCI_CLASS_BRIDGE_PCI:
> | + /* don't size subtractive decoding (transparent)
> | + * PCI-to-PCI bridges */
> | + if (bus->self->transparent)
> | + break;
> | pci_bridge_check_ranges(bus);
> | if (bus->self->is_hotplug_bridge) {
> | additional_io_size = pci_hotplug_io_size;
> `----
Ahh. I'd forgotten about that particular PCI patch.
That is definitely the right thing to do, and commit 8fa5913d54f3
("PCI: remove transparent bridge sizing") did exactly that, but then
we reverted it in commit 12c22d6ef299 because it caused some odd
problems for some people.
I think we should try to re-do that "avoid sizing transparent bridges"
commit, because it really should make it much easier to do PCI
allocations under some very common situations (there's a *lot* of
common intel transparent PCI bridges).
Jesse, Yinghai, Ram - should we try to just re-do that commit in this
merge window, and see how that goes? We can always revert it again if
it causes problems..
Linus
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