Messages in this thread Patch in this message |  | | | From | Andi Kleen <> | | Subject | [PATCH] [1/5] Only scan the root bus in early PCI quirks. | | Date | Mon, 5 Jan 2009 00:36:38 +0100 (CET) |
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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>
--- arch/x86/kernel/early-quirks.c | 22 ++++++++++++++-------- 1 file changed, 14 insertions(+), 8 deletions(-) Index: linux-2.6.28-test/arch/x86/kernel/early-quirks.c =================================================================== --- linux-2.6.28-test.orig/arch/x86/kernel/early-quirks.c 2008-11-24 16:42:46.000000000 +0100 +++ linux-2.6.28-test/arch/x86/kernel/early-quirks.c 2008-12-29 05:25:09.000000000 +0100 @@ -200,6 +200,12 @@ 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 @@ 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; + } }
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