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Commit 12f44f46 authored by Ivan Kokshaysky's avatar Ivan Kokshaysky Committed by Linus Torvalds
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[PATCH] pci: fixup parent subordinate busnr 



I believe the change that broke things is introduction of
pci_fixup_parent_subordinate_busnr().

The patch here does two things:
- hunk #1 should fix the problems you've seen when you boot without
  additional "pci" kernel options;
- hunk #2 supposedly fixes boot with "pci=assign-busses" option which
  otherwise hangs Acer TM81xx machines as reported.

Please try this with and without "pci=assign-busses". If it boots,
I'd like to see 'lspci -vvx' for both cases.

Signed-off-by: default avatarAndrew Morton <akpm@osdl.org>
Signed-off-by: default avatarLinus Torvalds <torvalds@osdl.org>
parent bfab08c0

drivers/pci/probe.c

+17 −1
Original line number Diff line number Diff line
@@ -402,6 +402,12 @@ static void pci_enable_crs(struct pci_dev *dev) 
static void __devinit pci_fixup_parent_subordinate_busnr(struct pci_bus *child, int max)

{

	struct pci_bus *parent = child->parent;



	/* Attempts to fix that up are really dangerous unless

	   we're going to re-assign all bus numbers. */

	if (!pcibios_assign_all_busses())

		return;



	while (parent->parent && parent->subordinate < max) {

		parent->subordinate = max;

		pci_write_config_byte(parent->self, PCI_SUBORDINATE_BUS, max);
@@ -478,8 +484,18 @@ int __devinit pci_scan_bridge(struct pci_bus *bus, struct pci_dev * dev, int max 
		 * We need to assign a number to this bus which we always

		 * do in the second pass.

		 */

		if (!pass)

		if (!pass) {

			if (pcibios_assign_all_busses())

				/* Temporarily disable forwarding of the

				   configuration cycles on all bridges in

				   this bus segment to avoid possible

				   conflicts in the second pass between two

				   bridges programmed with overlapping

				   bus ranges. */

				pci_write_config_dword(dev, PCI_PRIMARY_BUS,

						       buses & ~0xffffff);

			return max;

		}



		/* Clear errors */

		pci_write_config_word(dev, PCI_STATUS, 0xffff);