x86/PCI: fix bogus host bridge window start/end alignment from _CRS (03db42ad) · Commits · 戴 / test

PCI device BARs are guaranteed to start and end on at least a four-byte (I/O) or a sixteen-byte (MMIO) boundary because they're aligned on their size and the low BAR bits are reserved. PCI-to-PCI bridge apertures have even larger alignment restrictions. However, some BIOSes (e.g., HP DL360 BIOS P31) report host bridge windows like "[io 0x0000-0x2cfe]". This is wrong because it excludes the last port at 0x2cff: it's impossible for a downstream device to claim 0x2cfe without also claiming 0x2cff. In fact, this BIOS configures a device behind the bridge to "[io 0x2c00-0x2cff]", so we know the window actually does include 0x2cff. This patch rounds the start and end of apertures to the appropriate boundary. I experimentally determined that Windows contains a similar workaround; details here: http://bugzilla.kernel.org/show_bug.cgi?id=14337 Signed-off-by:

Bjorn Helgaas <bjorn.helgaas@hp.com> Signed-off-by:

Jesse Barnes <jbarnes@virtuousgeek.org>

arch/x86/pci/acpi.c

+25 −0

Original line number	Diff line number	Diff line
		@@ -59,6 +59,30 @@ bus_has_transparent_bridge(struct pci_bus *bus)
		return false;
		}

		static void
		align_resource(struct acpi_device bridge, struct resource res)
		{
		int align = (res->flags & IORESOURCE_MEM) ? 16 : 4;

		/*
		* Host bridge windows are not BARs, but the decoders on the PCI side
		* that claim this address space have starting alignment and length
		* constraints, so fix any obvious BIOS goofs.
		*/
		if (res->start & (align - 1)) {
		dev_printk(KERN_DEBUG, &bridge->dev,
		"host bridge window %pR invalid; "
		"aligning start to %d-byte boundary\n", res, align);
		res->start &= ~(align - 1);
		}
		if ((res->end + 1) & (align - 1)) {
		dev_printk(KERN_DEBUG, &bridge->dev,
		"host bridge window %pR invalid; "
		"aligning end to %d-byte boundary\n", res, align);
		res->end = roundup(res->end, align) - 1;
		}
		}

		static acpi_status
		setup_resource(struct acpi_resource acpi_res, void data)
		{
		@@ -107,6 +131,7 @@ setup_resource(struct acpi_resource acpi_res, void data)
		res->start = start;
		res->end = end;
		res->child = NULL;
		align_resource(info->bridge, res);

		if (!(pci_probe & PCI_USE__CRS)) {
		dev_printk(KERN_DEBUG, &info->bridge->dev,

Admin message