Messages in this thread Patch in this message | | | Subject | Re: [PATCH] PCI patches for 2.6.10 | Date | Mon, 10 Jan 2005 09:20:57 -0800 | From | Greg KH <> |
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ChangeSet 1.1938.447.8, 2004/12/17 13:44:31-08:00, macro@mips.com
[PATCH] PCI: Don't touch BARs of host bridges
BARs of host bridges often have special meaning and AFAIK are best left to be setup by the firmware or system-specific startup code and kept intact by the generic resource handler. For example a couple of host bridges used for MIPS processors interpret BARs as target-mode decoders for accessing host memory by PCI masters (which is quite reasonable). For them it's desirable to keep their decoded address range overlapping with the host RAM for simplicity if nothing else (I can imagine running out of address space with lots of memory and 32-bit PCI with no DAC support in the participating devices).
This is already the case with the i386 and ppc platform-specific PCI resource allocators. Please consider the following change for the generic allocator. Currently we have a pile of hacks implemented for host bridges to be left untouched and I'd be pleased to remove them.
From: "Maciej W. Rozycki" <macro@mips.com> Signed-off-by: Greg Kroah-Hartman <greg@kroah.com>
drivers/pci/setup-bus.c | 9 +++++++-- 1 files changed, 7 insertions(+), 2 deletions(-)
diff -Nru a/drivers/pci/setup-bus.c b/drivers/pci/setup-bus.c --- a/drivers/pci/setup-bus.c 2005-01-10 09:02:52 -08:00 +++ b/drivers/pci/setup-bus.c 2005-01-10 09:02:52 -08:00 @@ -57,8 +57,13 @@ list_for_each_entry(dev, &bus->devices, bus_list) { u16 class = dev->class >> 8; - if (class == PCI_CLASS_DISPLAY_VGA - || class == PCI_CLASS_NOT_DEFINED_VGA) + /* Don't touch classless devices and host bridges. */ + if (class == PCI_CLASS_NOT_DEFINED || + class == PCI_CLASS_BRIDGE_HOST) + continue; + + if (class == PCI_CLASS_DISPLAY_VGA || + class == PCI_CLASS_NOT_DEFINED_VGA) bus->bridge_ctl |= PCI_BRIDGE_CTL_VGA; pdev_sort_resources(dev, &head); - To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/
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