diff options
| author | Bjorn Helgaas <bjorn.helgaas@hp.com> | 2009-11-04 10:39:18 -0700 |
|---|---|---|
| committer | Jesse Barnes <jbarnes@virtuousgeek.org> | 2009-11-04 13:06:46 -0800 |
| commit | 03db42adfeeabe856dbb6894dd3aaff55838330a (patch) | |
| tree | f78101e96ce2171a503bd1119d08d89e31118a69 /arch/x86/pci/acpi.c | |
| parent | f1db6fde09e201218f488d7205a7cd7bc448d496 (diff) | |
x86/PCI: fix bogus host bridge window start/end alignment from _CRS
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>
Diffstat (limited to 'arch/x86/pci/acpi.c')
| -rw-r--r-- | arch/x86/pci/acpi.c | 25 |
1 files changed, 25 insertions, 0 deletions
diff --git a/arch/x86/pci/acpi.c b/arch/x86/pci/acpi.c index 54db5a04b5e1..8ddf4f4c7253 100644 --- a/arch/x86/pci/acpi.c +++ b/arch/x86/pci/acpi.c @@ -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, |