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x86, apic: Clear APIC Timer Initial Count Register on shutdown
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Commit a98f8fd (x86: apic reset
counter on shutdown) set the counter to max to avoid spurious
interrupts when the timer is re-enabled.

(In theory) you'll still get a spurious interrupt if spending
more than 344 seconds with this interrupt disabled and then
unmasking it.

The right thing to do is to clear the register. This disables
the interrupt from happening (at least it does on AMD hardware).

Signed-off-by: Andreas Herrmann <andreas.herrmann3@amd.com>
LKML-Reference: <20091027100138.GB30802@alberich.amd.com>
Signed-off-by: Ingo Molnar <mingo@elte.hu>
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Andreas Herrmann authored and Ingo Molnar committed Oct 27, 2009
1 parent f88f2b4 commit 6f9b410
Showing 1 changed file with 1 addition and 1 deletion.
2 changes: 1 addition & 1 deletion arch/x86/kernel/apic/apic.c
Original file line number Diff line number Diff line change
@@ -444,7 +444,7 @@ static void lapic_timer_setup(enum clock_event_mode mode,
v = apic_read(APIC_LVTT);
v |= (APIC_LVT_MASKED | LOCAL_TIMER_VECTOR);
apic_write(APIC_LVTT, v);
apic_write(APIC_TMICT, 0xffffffff);
apic_write(APIC_TMICT, 0);
break;
case CLOCK_EVT_MODE_RESUME:
/* Nothing to do here */

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