PCI: Align bridge I/O windows as required by downstream devices & bridges
An upstream bridge's I/O window must be at least as aligned as any
downstream device or bridge requires. In particular, if the upstream
bridge supports 1K alignment but a downstream bridge requires 4K alignment,
the upstream window must also be 4K aligned.
Therefore, do not reduce the required alignment ("min_align") based on
the upstream bridge's capabilities.
Reported-by: Wei Yang <weiyang@linux.vnet.ibm.com>
Suggested-by: Yinghai Lu <yinghai@kernel.org>
Signed-off-by: Bjorn Helgaas <bhelgaas@google.com>diff --git a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c
index d4f1ad9..8333c92 100644
--- a/drivers/pci/setup-bus.c
+++ b/drivers/pci/setup-bus.c
@@ -749,12 +749,12 @@
struct resource *b_res = find_free_bus_resource(bus, IORESOURCE_IO);
resource_size_t size = 0, size0 = 0, size1 = 0;
resource_size_t children_add_size = 0;
- resource_size_t min_align, io_align, align;
+ resource_size_t min_align, align;
if (!b_res)
return;
- io_align = min_align = window_alignment(bus, IORESOURCE_IO);
+ min_align = window_alignment(bus, IORESOURCE_IO);
list_for_each_entry(dev, &bus->devices, bus_list) {
int i;
@@ -781,9 +781,6 @@
}
}
- if (min_align > io_align)
- min_align = io_align;
-
size0 = calculate_iosize(size, min_size, size1,
resource_size(b_res), min_align);
if (children_add_size > add_size)