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Subject[patch 01/71] x86-32: AMD c1e force timer broadcast late
2.6.26-stable review patch.  If anyone has any objections, please let us know.

------------------
From: Chuck Ebbert <cebbert@redhat.com>

This patch is not needed in 2.6.27 because it has new c1e-aware idle code.

In kernel 2.6.26 the 32-bit x86 timers are started earlier than before.
This breaks AMD c1e detection trying to force timer broadcast for the
local apic timer. Copy the code from the 64-bit kernel to force timer
broadcast late.

Reference:
http://bugzilla.kernel.org/show_bug.cgi?id=11427

Signed-off-by: Chuck Ebbert <cebbert@redhat.com>
Acked-by: Thomas Gleixner <tglx@linutronix.de>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

---
arch/x86/kernel/apic_32.c | 25 ++++++++++++++++++++++++-
1 file changed, 24 insertions(+), 1 deletion(-)

--- a/arch/x86/kernel/apic_32.c
+++ b/arch/x86/kernel/apic_32.c
@@ -552,8 +552,31 @@ void __init setup_boot_APIC_clock(void)
setup_APIC_timer();
}

-void __devinit setup_secondary_APIC_clock(void)
+/*
+ * AMD C1E enabled CPUs have a real nasty problem: Some BIOSes set the
+ * C1E flag only in the secondary CPU, so when we detect the wreckage
+ * we already have enabled the boot CPU local apic timer. Check, if
+ * disable_apic_timer is set and the DUMMY flag is cleared. If yes,
+ * set the DUMMY flag again and force the broadcast mode in the
+ * clockevents layer.
+ */
+static void __cpuinit check_boot_apic_timer_broadcast(void)
+{
+ if (!local_apic_timer_disabled ||
+ (lapic_clockevent.features & CLOCK_EVT_FEAT_DUMMY))
+ return;
+
+ lapic_clockevent.features |= CLOCK_EVT_FEAT_DUMMY;
+
+ local_irq_enable();
+ clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_FORCE,
+ &boot_cpu_physical_apicid);
+ local_irq_disable();
+}
+
+void __cpuinit setup_secondary_APIC_clock(void)
{
+ check_boot_apic_timer_broadcast();
setup_APIC_timer();
}

--


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