Revert "PCI: update bridge resources to get more big ranges in PCI assign unssigned"

This reverts commit 977d17bb1749517b353874ccdc9b85abc7a58c2a, because it
can cause problems with some devices not getting any resources at all
when the resource tree is re-allocated.

For an example of this, see

	https://bugzilla.kernel.org/show_bug.cgi?id=15960
	(originally https://bugtrack.alsa-project.org/alsa-bug/view.php?id=4982)
	(lkml thread: http://lkml.org/lkml/2010/4/19/20)

where Peter Henriksson reported his Xonar DX sound card gone, because
the IO port region was no longer allocated.

Reported-bisected-and-tested-by: Peter Henriksson <peter.henriksson@gmail.com>
Requested-by: Andrew Morton <akpm@linux-foundation.org>
Requested-by: Clemens Ladisch <clemens@ladisch.de>
Acked-by: Jesse Barnes <jbarnes@virtuousgeek.org>
Cc: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

drivers/pci/setup-bus.c

@@ -838,65 +838,11 @@ static void pci_bus_dump_resources(struct pci_bus *bus)
 	}
 }
 
-static int __init pci_bus_get_depth(struct pci_bus *bus)
-{
-	int depth = 0;
-	struct pci_dev *dev;
-
-	list_for_each_entry(dev, &bus->devices, bus_list) {
-		int ret;
-		struct pci_bus *b = dev->subordinate;
-		if (!b)
-			continue;
-
-		ret = pci_bus_get_depth(b);
-		if (ret + 1 > depth)
-			depth = ret + 1;
-	}
-
-	return depth;
-}
-static int __init pci_get_max_depth(void)
-{
-	int depth = 0;
-	struct pci_bus *bus;
-
-	list_for_each_entry(bus, &pci_root_buses, node) {
-		int ret;
-
-		ret = pci_bus_get_depth(bus);
-		if (ret > depth)
-			depth = ret;
-	}
-
-	return depth;
-}
-
-/*
- * first try will not touch pci bridge res
- * second  and later try will clear small leaf bridge res
- * will stop till to the max  deepth if can not find good one
- */
 void __init
 pci_assign_unassigned_resources(void)
 {
 	struct pci_bus *bus;
-	int tried_times = 0;
-	enum release_type rel_type = leaf_only;
-	struct resource_list_x head, *list;
-	unsigned long type_mask = IORESOURCE_IO | IORESOURCE_MEM |
-				  IORESOURCE_PREFETCH;
-	unsigned long failed_type;
-	int max_depth = pci_get_max_depth();
-	int pci_try_num;
 
-	head.next = NULL;
-
-	pci_try_num = max_depth + 1;
-	printk(KERN_DEBUG "PCI: max bus depth: %d pci_try_num: %d\n",
-		 max_depth, pci_try_num);
-
-again:
 	/* Depth first, calculate sizes and alignments of all
 	   subordinate buses. */
 	list_for_each_entry(bus, &pci_root_buses, node) {
@@ -904,65 +850,9 @@ again:
 	}
 	/* Depth last, allocate resources and update the hardware. */
 	list_for_each_entry(bus, &pci_root_buses, node) {
-		__pci_bus_assign_resources(bus, &head);
-	}
-	tried_times++;
-
-	/* any device complain? */
-	if (!head.next)
-		goto enable_and_dump;
-	failed_type = 0;
-	for (list = head.next; list;) {
-		failed_type |= list->flags;
-		list = list->next;
-	}
-	/*
-	 * io port are tight, don't try extra
-	 * or if reach the limit, don't want to try more
-	 */
-	failed_type &= type_mask;
-	if ((failed_type == IORESOURCE_IO) || (tried_times >= pci_try_num)) {
-		free_failed_list(&head);
-		goto enable_and_dump;
-	}
-
-	printk(KERN_DEBUG "PCI: No. %d try to assign unassigned res\n",
-			 tried_times + 1);
-
-	/* third times and later will not check if it is leaf */
-	if ((tried_times + 1) > 2)
-		rel_type = whole_subtree;
-
-	/*
-	 * Try to release leaf bridge's resources that doesn't fit resource of
-	 * child device under that bridge
-	 */
-	for (list = head.next; list;) {
-		bus = list->dev->bus;
-		pci_bus_release_bridge_resources(bus, list->flags & type_mask,
-						  rel_type);
-		list = list->next;
-	}
-	/* restore size and flags */
-	for (list = head.next; list;) {
-		struct resource *res = list->res;
-
-		res->start = list->start;
-		res->end = list->end;
-		res->flags = list->flags;
-		if (list->dev->subordinate)
-			res->flags = 0;
-
-		list = list->next;
-	}
-	free_failed_list(&head);
-
-	goto again;
-
-enable_and_dump:
-	/* Depth last, update the hardware. */
-	list_for_each_entry(bus, &pci_root_buses, node)
+		pci_bus_assign_resources(bus);
 		pci_enable_bridges(bus);
+	}
 
 	/* dump the resource on buses */
 	list_for_each_entry(bus, &pci_root_buses, node) {