path: root/arch/x86/kernel/early-quirks.c
diff options
authorAndi Kleen <andi@firstfloor.org>2009-01-09 20:17:39 (GMT)
committerLinus Torvalds <torvalds@linux-foundation.org>2009-01-09 20:46:22 (GMT)
commit8659c406ade32f47da2c95889094801921d6330a (patch)
treeb2b263f1adda20a07415db7683f9807a903dc60e /arch/x86/kernel/early-quirks.c
parent4ce5f24193cef2e26f182ce708e94ba1f5fafc0c (diff)
x86: only scan the root bus in early PCI quirks
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> Cc: Ingo Molnar <mingo@elte.hu> Cc: Thomas Gleixner <tglx@linutronix.de> Cc: "H. Peter Anvin" <hpa@zytor.com> Cc: Jesse Barnes <jbarnes@virtuousgeek.org> Signed-off-by: Andrew Morton <akpm@linux-foundation.org> Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
Diffstat (limited to 'arch/x86/kernel/early-quirks.c')
1 files changed, 14 insertions, 8 deletions
diff --git a/arch/x86/kernel/early-quirks.c b/arch/x86/kernel/early-quirks.c
index 744aa7f..76b8cd9 100644
--- a/arch/x86/kernel/early-quirks.c
+++ b/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 = {
@@ -267,17 +273,17 @@ static int __init check_dev_quirk(int num, int slot, int func)
void __init early_quirks(void)
- int num, slot, func;
+ int slot, func;
if (!early_pci_allowed())
/* 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;
+ }

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