The patch titled
x86: only scan the root bus in early PCI quirks
has been added to the -mm tree. Its filename is
x86-only-scan-the-root-bus-in-early-pci-quirks.patch
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The current -mm tree may be found at http://userweb.kernel.org/~akpm/mmotm/
------------------------------------------------------
Subject: x86: only scan the root bus in early PCI quirks
From: Andi Kleen <andi@xxxxxxxxxxxxxx>
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@xxxxxxxxxxxxxxx>
Cc: Linus Torvalds <torvalds@xxxxxxxxxxxxxxxxxxxx>
Cc: Ingo Molnar <mingo@xxxxxxx>
Cc: Thomas Gleixner <tglx@xxxxxxxxxxxxx>
Cc: "H. Peter Anvin" <hpa@xxxxxxxxx>
Cc: Jesse Barnes <jbarnes@xxxxxxxxxxxxxxxx>
Signed-off-by: Andrew Morton <akpm@xxxxxxxxxxxxxxxxxxxx>
---
arch/x86/kernel/early-quirks.c | 22 ++++++++++++++--------
1 file changed, 14 insertions(+), 8 deletions(-)
diff -puN arch/x86/kernel/early-quirks.c~x86-only-scan-the-root-bus-in-early-pci-quirks arch/x86/kernel/early-quirks.c
--- a/arch/x86/kernel/early-quirks.c~x86-only-scan-the-root-bus-in-early-pci-quirks
+++ a/arch/x86/kernel/early-quirks.c
@@ -201,6 +201,12 @@ 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 },
@@ -267,17 +273,17 @@ 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;
+ }
}
_
Patches currently in -mm which might be from andi@xxxxxxxxxxxxxx are
origin.patch
x86-only-scan-the-root-bus-in-early-pci-quirks.patch
remove-remaining-unwinder-code.patch
elf-implement-at_random-for-glibc-prng-seeding.patch
nilfs2-fix-problems-of-memory-allocation-in-ioctl.patch
allow-hpet-force-enable-on-ich10-hpet.patch
mark-complex-bitopsh-inlines-as-__always_inline.patch
avoid-theoretical-vmalloc-fault-loop.patch
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