[PATCH] PCI: use bus numbers sparsely, if necessary
Add a warning if a child bus may be inaccessible because the
parent bridge has wrong secondary or subordinate bus numbers.
Note that this may or may not happen on "transparent" bridges,
as can be seen in bug #5557.
Also, if we do not fix up the assignment of bus numbers, try to
make use of the bus number space available.
Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index 00ba6a0..3c9834d 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -433,7 +433,7 @@
{
struct pci_bus *child;
int is_cardbus = (dev->hdr_type == PCI_HEADER_TYPE_CARDBUS);
- u32 buses, i;
+ u32 buses, i, j = 0;
u16 bctl;
pci_read_config_dword(dev, PCI_PRIMARY_BUS, &buses);
@@ -543,10 +543,29 @@
* as cards with a PCI-to-PCI bridge can be
* inserted later.
*/
- for (i=0; i<CARDBUS_RESERVE_BUSNR; i++)
+ for (i=0; i<CARDBUS_RESERVE_BUSNR; i++) {
+ struct pci_bus *parent = bus;
if (pci_find_bus(pci_domain_nr(bus),
max+i+1))
break;
+ while (parent->parent) {
+ if ((!pcibios_assign_all_busses()) &&
+ (parent->subordinate > max) &&
+ (parent->subordinate <= max+i)) {
+ j = 1;
+ }
+ parent = parent->parent;
+ }
+ if (j) {
+ /*
+ * Often, there are two cardbus bridges
+ * -- try to leave one valid bus number
+ * for each one.
+ */
+ i /= 2;
+ break;
+ }
+ }
max += i;
pci_fixup_parent_subordinate_busnr(child, max);
}
@@ -561,6 +580,22 @@
sprintf(child->name, (is_cardbus ? "PCI CardBus #%02x" : "PCI Bus #%02x"), child->number);
+ while (bus->parent) {
+ if ((child->subordinate > bus->subordinate) ||
+ (child->number > bus->subordinate) ||
+ (child->number < bus->number) ||
+ (child->subordinate < bus->number)) {
+ printk(KERN_WARNING "PCI: Bus #%02x (-#%02x) may be "
+ "hidden behind%s bridge #%02x (-#%02x)%s\n",
+ child->number, child->subordinate,
+ bus->self->transparent ? " transparent" : " ",
+ bus->number, bus->subordinate,
+ pcibios_assign_all_busses() ? " " :
+ " (try 'pci=assign-busses')");
+ }
+ bus = bus->parent;
+ }
+
return max;
}