From 90b54929b626c80056262d9d99b3f48522e404d0 Mon Sep 17 00:00:00 2001 From: Ivan Kokshaysky Date: Tue, 7 Jun 2005 04:07:02 +0400 Subject: [PATCH] [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: Ivan Kokshaysky Acked-by: Dominik Brodowski Signed-off-by: Greg Kroah-Hartman --- drivers/pci/probe.c | 5 ++--- 1 file changed, 2 insertions(+), 3 deletions(-) diff --git a/drivers/pci/probe.c b/drivers/pci/probe.c index 9392ff3fb8..df3bdae204 100644 --- a/drivers/pci/probe.c +++ b/drivers/pci/probe.c @@ -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++) -- 2.39.5