[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: Andrew Morton <akpm@osdl.org>
Signed-off-by: Linus Torvalds <torvalds@osdl.org>
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index c77d5b1..0057864 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -402,6 +402,12 @@
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 @@
* 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);