From: Len Brown <len.brown@xxxxxxxxx> When ACPI is asked to find an MADT (APIC table) and fails, then ACPI expects to run in PIC mode. However, if an MP Table is was found, IRQs will be registered as if an IOAPIC is being used, even though ACPI is configuring interrupt links links for PIC mode. In this scenario, disable MPS so that IRQs are registered in PIC mode, consistent with ACPI. http://bugzilla.kernel.org/show_bug.cgi?id=12257 Signed-off-by: Len Brown <len.brown@xxxxxxxxx> --- arch/x86/kernel/acpi/boot.c | 11 +++++++++++ 1 files changed, 11 insertions(+), 0 deletions(-) diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c index 4c51a2f..de8ce79 100644 --- a/arch/x86/kernel/acpi/boot.c +++ b/arch/x86/kernel/acpi/boot.c @@ -1359,6 +1359,17 @@ static void __init acpi_process_madt(void) "Invalid BIOS MADT, disabling ACPI\n"); disable_acpi(); } + } else { + /* + * ACPI found no MADT, and so ACPI wants UP PIC mode. + * In the event an MPS table was found, forget it. + * Boot with "acpi=off" to use MPS on such a system. + */ + if (smp_found_config) { + printk(KERN_WARNING PREFIX + "No APIC-table, disabling MPS\n"); + smp_found_config = 0; + } } #endif return; -- 1.5.6.6 -- To unsubscribe from this list: send the line "unsubscribe linux-acpi" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
