i386: Use global flag to disable broken local apic timer on AMD CPUs.

The Averatec 2370 and some other Turion laptop BIOS seems to program the
ENABLE_C1E MSR inconsistently between cores. This confuses the lapic
use heuristics because when C1E is enabled anywhere it seems to affect
the complete chip.

Use a global flag instead of a per cpu flag to handle this.
If any CPU has C1E enabled disabled lapic use.

Thanks to Cal Peake for debugging.

Cc: tglx@linutronix.de
Signed-off-by: Andi Kleen <ak@suse.de>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>

1 files changed, 4 insertions, 6 deletions

diff --git a/arch/i386/kernel/apic.c b/arch/i386/kernel/apic.c
index bfc6cb7df7e7..f9fff29e01a9 100644
--- a/arch/i386/kernel/apic.c
+++ b/arch/i386/kernel/apic.c
@@ -61,8 +61,9 @@ static int enable_local_apic __initdata = 0;
 
 /* Local APIC timer verification ok */
 static int local_apic_timer_verify_ok;
-/* Disable local APIC timer from the kernel commandline or via dmi quirk */
-static int local_apic_timer_disabled;
+/* Disable local APIC timer from the kernel commandline or via dmi quirk
+   or using CPU MSR check */
+int local_apic_timer_disabled;
 /* Local APIC timer works in C2 */
 int local_apic_timer_c2_ok;
 EXPORT_SYMBOL_GPL(local_apic_timer_c2_ok);
@@ -370,12 +371,9 @@ void __init setup_boot_APIC_clock(void)
         long delta, deltapm;
         int pm_referenced = 0;
 
-        if (boot_cpu_has(X86_FEATURE_LAPIC_TIMER_BROKEN))
-                local_apic_timer_disabled = 1;
-
         /*
          * The local apic timer can be disabled via the kernel
-         * commandline or from the test above. Register the lapic
+         * commandline or from the CPU detection code. Register the lapic
          * timer as a dummy clock event source on SMP systems, so the
          * broadcast mechanism is used. On UP systems simply ignore it.
          */