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Commit 90b54929 authored by Ivan Kokshaysky's avatar Ivan Kokshaysky Committed by Greg Kroah-Hartman
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[PATCH] PCI: handle subtractive decode pci-pci bridge better 



With the number of PCI bus resources increased to 8, we can
handle the subtractive decode PCI-PCI bridge like a normal
bridge, taking into account standard PCI-PCI bridge windows
(resources 0-2). This helps to avoid problems with peer-to-peer DMA
behind such bridges, poor performance for MMIO ranges outside bridge
windows and prefetchable vs. non-prefetchable memory issues.

To reflect the fact that such bridges do forward all addresses to
the secondary bus (transparency), remaining bus resources 3-7 are
linked to resources 0-4 of the primary bus. These resources will be
used as fallback by resource management code if allocation from
standard bridge windows fails for some reason.

Signed-off-by: default avatarIvan Kokshaysky <ink@jurassic.park.msu.ru>
Acked-by: default avatarDominik Brodowski <linux@dominikbrodowski.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent a03fa955

drivers/pci/probe.c

+2 −3
Original line number Diff line number Diff line
@@ -239,9 +239,8 @@ void __devinit pci_read_bridge_bases(struct pci_bus *child) 


	if (dev->transparent) {

		printk(KERN_INFO "PCI: Transparent bridge - %s\n", pci_name(dev));

		for(i = 0; i < PCI_BUS_NUM_RESOURCES; i++)

			child->resource[i] = child->parent->resource[i];

		return;

		for(i = 3; i < PCI_BUS_NUM_RESOURCES; i++)

			child->resource[i] = child->parent->resource[i - 3];

	}



	for(i=0; i<3; i++)