diff options
| author | Maciej W. Rozycki <macro@linux-mips.org> | 2008-07-01 01:11:35 +0100 |
|---|---|---|
| committer | Ingo Molnar <mingo@elte.hu> | 2008-07-08 11:10:32 +0200 |
| commit | 471694ea6c6ccdf7131354f1d698d4d83a605293 (patch) | |
| tree | b2fbc18e8236fd5074250157eacf0bca84fe8be2 | |
| parent | bad48f4b313a756ccde454c25c14c828e2fd5819 (diff) | |
x86, ioapic, acpi: add a knob to disable IRQ 0 through I/O APIC
As discovered recently some systems exhibit problems when the 8254 timer
IRQ is routed through the I/O APIC. These problems do not affect the
timer IRQ itself and therefore cannot be detected when the correctness of
operation of the interrupt is verified in check_timer(). Therefore the
I/O APIC path of the timer IRQ has to be disabled entirely.
This is a change that lets platforms ask for the timer IRQ not to be
registered in the I/O APIC interrupt tables. The local APIC and ExtINTA
paths are unaffected. This request is only taken into account for ACPI
platforms as MP table systems seem unaffected so far.
Signed-off-by: Maciej W. Rozycki <macro@linux-mips.org>
Cc: Len Brown <lenb@kernel.org>
Cc: Matthew Garrett <mjg59@srcf.ucam.org>
Cc: "Rafael J. Wysocki" <rjw@sisk.pl>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
| -rw-r--r-- | arch/x86/kernel/acpi/boot.c | 10 |
1 files changed, 10 insertions, 0 deletions
diff --git a/arch/x86/kernel/acpi/boot.c b/arch/x86/kernel/acpi/boot.c index 91bb9a99338..92a54265395 100644 --- a/arch/x86/kernel/acpi/boot.c +++ b/arch/x86/kernel/acpi/boot.c @@ -83,6 +83,8 @@ int acpi_lapic; int acpi_ioapic; int acpi_strict; +static int disable_irq0_through_ioapic __initdata; + u8 acpi_sci_flags __initdata; int acpi_sci_override_gsi __initdata; int acpi_skip_timer_override __initdata; @@ -992,6 +994,10 @@ void __init mp_override_legacy_irq(u8 bus_irq, u8 polarity, u8 trigger, u32 gsi) int pin; struct mp_config_intsrc mp_irq; + /* Skip the 8254 timer interrupt (IRQ 0) if requested. */ + if (bus_irq == 0 && disable_irq0_through_ioapic) + return; + /* * Convert 'gsi' to 'ioapic.pin'. */ @@ -1058,6 +1064,10 @@ void __init mp_config_acpi_legacy_irqs(void) for (i = 0; i < 16; i++) { int idx; + /* Skip the 8254 timer interrupt (IRQ 0) if requested. */ + if (i == 0 && disable_irq0_through_ioapic) + continue; + for (idx = 0; idx < mp_irq_entries; idx++) { struct mp_config_intsrc *irq = mp_irqs + idx; |