Move xen patchset to new version's subdir.

[people/pmueller/ipfire-2.x.git] / src / patches / suse-2.6.27.31 / patches.arch / x86_restrict_pci_early_quirks_to_root_bridges.patch

From: Andi Kleen <ak@linux.intel.com>
Subject: Only scan the root bus in early PCI quirks.
References: bnc#57886
Patch-Mainline: submitted for .29

We found a situation on Linus' machine that the Nvidia timer
quirk hit on a Intel chipset system. The problem is that the
system has a fancy Nvidia card with an own PCI bridge, and
the early-quirks code looking for any NVidia bridge triggered
on it incorrectly. This didn't lead a boot failure by luck,
but the timer routing code selecting the wrong timer first and 
some ugly messages. It might lead to real problems on
other systems.

I checked all the devices which are currently checked for
by early_quirks and it turns out they are all located in 
the root bus zero.

So change the early-quirks loop to only scan bus 0. This
incidently also saves quite some unnecessary scanning work,
because early_quirks doesn't go through all the non root
busses.

The graphics card is not on bus 0, so it is not matched
anymore.

Signed-off-by: Andi Kleen <ak@linux.intel.com>
Signed-off-by: Thomas Renninger <trenn@suse.de>

Index: linux-2.6.28-rc5-test/arch/x86/kernel/early-quirks.c
===================================================================
--- linux-2.6.28-rc5-test.orig/arch/x86/kernel/early-quirks.c
+++ linux-2.6.28-rc5-test/arch/x86/kernel/early-quirks.c
@@ -200,6 +200,12 @@ struct chipset {
 	void (*f)(int num, int slot, int func);
 };
 
+/*
+ * Only works for devices on the root bus. If you add any devices
+ * not on bus 0 readd another loop level in early_quirks(). But
+ * be careful because at least the Nvidia quirk here relies on
+ * only matching on bus 0.
+ */
 static struct chipset early_qrk[] __initdata = {
 	{ PCI_VENDOR_ID_NVIDIA, PCI_ANY_ID,
 	  PCI_CLASS_BRIDGE_PCI, PCI_ANY_ID, QFLAG_APPLY_ONCE, nvidia_bugs },
@@ -266,17 +272,17 @@ static int __init check_dev_quirk(int nu
 
 void __init early_quirks(void)
 {
-	int num, slot, func;
+	int slot, func;
 
 	if (!early_pci_allowed())
 		return;
 
 	/* Poor man's PCI discovery */
-	for (num = 0; num < 32; num++)
-		for (slot = 0; slot < 32; slot++)
-			for (func = 0; func < 8; func++) {
-				/* Only probe function 0 on single fn devices */
-				if (check_dev_quirk(num, slot, func))
-					break;
-			}
+	/* Only scan the root bus */
+	for (slot = 0; slot < 32; slot++)
+		for (func = 0; func < 8; func++) {
+			/* Only probe function 0 on single fn devices */
+			if (check_dev_quirk(0, slot, func))
+				break;
+		}
 }