PCI: Don't shrink too much for hotplug bridge
Otherwise may have problem later if we plug pcie cards with bridges.
Signed-off-by: Yinghai Lu <yinghai@kernel.org>
diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c
index e3ec7c2..dbcfc68 100644
--- a/drivers/pci/probe.c
+++ b/drivers/pci/probe.c
@@ -1000,6 +1000,7 @@
static unsigned int __pci_scan_child_bus(struct pci_bus *bus,
int pass);
+#define HOTPLUG_BRIDGE_RESERVE_BUSNR 8
/*
* If it's a bridge, configure it and scan the bus behind it.
* For CardBus bridges, we don't scan behind as the devices will
@@ -1168,6 +1169,11 @@
/*
* Set the subordinate bus number to its real value.
*/
+ if (dev->is_hotplug_bridge && child->busn_res.end > max &&
+ (max - child->busn_res.start) < HOTPLUG_BRIDGE_RESERVE_BUSNR)
+ max = min_t(int, child->busn_res.start +
+ HOTPLUG_BRIDGE_RESERVE_BUSNR,
+ child->busn_res.end);
shrink_size = (int)child->busn_res.end - max;
pci_write_config_byte(dev, PCI_SUBORDINATE_BUS, max);
pci_bus_update_busn_res_end(child, max);
