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Commit 2d1d6678 authored by Bjorn Helgaas's avatar Bjorn Helgaas
Browse files

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: default avatarWei Yang <weiyang@linux.vnet.ibm.com>
Suggested-by: default avatarYinghai Lu <yinghai@kernel.org>
Signed-off-by: default avatarBjorn Helgaas <bhelgaas@google.com>
parent 11251a86

drivers/pci/setup-bus.c

+2 −5
Original line number Diff line number Diff line
@@ -749,12 +749,12 @@ static void pbus_size_io(struct pci_bus *bus, resource_size_t min_size, 
	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 @@ static void pbus_size_io(struct pci_bus *bus, resource_size_t min_size, 
		}

	}



	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)