ACPI: acpi_pad: Don't needlessly mark LAPIC unstable

As suggested in Venki's suggestion in the commit 0dc698b,
add LAPIC unstable detection in the acpi_pad drvier too.

Signed-off-by: Chen Gong <gong.chen@linux.intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

diff --git a/drivers/acpi/acpi_pad.c b/drivers/acpi/acpi_pad.c
index d269a8f3329cc0cbe9b5bcc8120c6a5b1c5320b7..446aced33aff81d7a2c4a949abce8979006db720 100644 (file)
--- a/drivers/acpi/acpi_pad.c
+++ b/drivers/acpi/acpi_pad.c
@@ -46,6 +46,8 @@ static unsigned long power_saving_mwait_eax;
 
 static unsigned char tsc_detected_unstable;
 static unsigned char tsc_marked_unstable;
+static unsigned char lapic_detected_unstable;
+static unsigned char lapic_marked_unstable;
 
 static void power_saving_mwait_init(void)
 {
@@ -75,9 +77,6 @@ static void power_saving_mwait_init(void)
        power_saving_mwait_eax = (highest_cstate << MWAIT_SUBSTATE_SIZE) |
                (highest_subcstate - 1);
 
-       for_each_online_cpu(i)
-               clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ON, &i);
-
 #if defined(CONFIG_GENERIC_TIME) && defined(CONFIG_X86)
        switch (boot_cpu_data.x86_vendor) {
        case X86_VENDOR_AMD:
@@ -86,13 +85,15 @@ static void power_saving_mwait_init(void)
                 * AMD Fam10h TSC will tick in all
                 * C/P/S0/S1 states when this bit is set.
                 */
-               if (boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
-                       return;
-
-               /*FALL THROUGH*/
+               if (!boot_cpu_has(X86_FEATURE_NONSTOP_TSC))
+                       tsc_detected_unstable = 1;
+               if (!boot_cpu_has(X86_FEATURE_ARAT))
+                       lapic_detected_unstable = 1;
+               break;
        default:
-               /* TSC could halt in idle */
+               /* TSC & LAPIC could halt in idle */
                tsc_detected_unstable = 1;
+               lapic_detected_unstable = 1;
        }
 #endif
 }
@@ -180,10 +181,20 @@ static int power_saving_thread(void *data)
                                mark_tsc_unstable("TSC halts in idle");
                                tsc_marked_unstable = 1;
                        }
+                       if (lapic_detected_unstable && !lapic_marked_unstable) {
+                               int i;
+                               /* LAPIC could halt in idle, so notify users */
+                               for_each_online_cpu(i)
+                                       clockevents_notify(
+                                               CLOCK_EVT_NOTIFY_BROADCAST_ON,
+                                               &i);
+                               lapic_marked_unstable = 1;
+                       }
                        local_irq_disable();
                        cpu = smp_processor_id();
-                       clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_ENTER,
-                               &cpu);
+                       if (lapic_marked_unstable)
+                               clockevents_notify(
+                                       CLOCK_EVT_NOTIFY_BROADCAST_ENTER, &cpu);
                        stop_critical_timings();
 
                        __monitor((void *)&current_thread_info()->flags, 0, 0);
@@ -192,8 +203,9 @@ static int power_saving_thread(void *data)
                                __mwait(power_saving_mwait_eax, 1);
 
                        start_critical_timings();
-                       clockevents_notify(CLOCK_EVT_NOTIFY_BROADCAST_EXIT,
-                               &cpu);
+                       if (lapic_marked_unstable)
+                               clockevents_notify(
+                                       CLOCK_EVT_NOTIFY_BROADCAST_EXIT, &cpu);
                        local_irq_enable();
 
                        if (jiffies > expire_time) {