1 files changed, 28 insertions, 4 deletions

diff --git a/drivers/acpi/processor_idle.c b/drivers/acpi/processor_idle.c
index 0721a8183c89..eb1f82f79153 100644
--- a/drivers/acpi/processor_idle.c
+++ b/drivers/acpi/processor_idle.c
@@ -357,6 +357,26 @@ int acpi_processor_resume(struct acpi_device * device)
         return 0;
 }
 
+#if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86_TSC)
+static int tsc_halts_in_c(int state)
+{
+        switch (boot_cpu_data.x86_vendor) {
+        case X86_VENDOR_AMD:
+                /*
+                 * AMD Fam10h TSC will tick in all
+                 * C/P/S0/S1 states when this bit is set.
+                 */
+                if (boot_cpu_has(X86_FEATURE_CONSTANT_TSC))
+                        return 0;
+                /*FALL THROUGH*/
+        case X86_VENDOR_INTEL:
+                /* Several cases known where TSC halts in C2 too */
+        default:
+                return state > ACPI_STATE_C1;
+        }
+}
+#endif
+
 #ifndef CONFIG_CPU_IDLE
 static void acpi_processor_idle(void)
 {
@@ -516,7 +536,8 @@ static void acpi_processor_idle(void)
 
 #if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86_TSC)
                 /* TSC halts in C2, so notify users */
-                mark_tsc_unstable("possible TSC halt in C2");
+                if (tsc_halts_in_c(ACPI_STATE_C2))
+                        mark_tsc_unstable("possible TSC halt in C2");
 #endif
                 /* Compute time (ticks) that we were actually asleep */
                 sleep_ticks = ticks_elapsed(t1, t2);
@@ -580,7 +601,8 @@ static void acpi_processor_idle(void)
 
 #if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86_TSC)
                 /* TSC halts in C3, so notify users */
-                mark_tsc_unstable("TSC halts in C3");
+                if (tsc_halts_in_c(ACPI_STATE_C3))
+                        mark_tsc_unstable("TSC halts in C3");
 #endif
                 /* Compute time (ticks) that we were actually asleep */
                 sleep_ticks = ticks_elapsed(t1, t2);
@@ -1445,7 +1467,8 @@ static int acpi_idle_enter_simple(struct cpuidle_device *dev,
 
 #if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86_TSC)
         /* TSC could halt in idle, so notify users */
-        mark_tsc_unstable("TSC halts in idle");;
+        if (tsc_halts_in_c(cx->type))
+                mark_tsc_unstable("TSC halts in idle");;
 #endif
         sleep_ticks = ticks_elapsed(t1, t2);
 
@@ -1556,7 +1579,8 @@ static int acpi_idle_enter_bm(struct cpuidle_device *dev,
 
 #if defined (CONFIG_GENERIC_TIME) && defined (CONFIG_X86_TSC)
         /* TSC could halt in idle, so notify users */
-        mark_tsc_unstable("TSC halts in idle");
+        if (tsc_halts_in_c(ACPI_STATE_C3))
+                mark_tsc_unstable("TSC halts in idle");
 #endif
         sleep_ticks = ticks_elapsed(t1, t2);
         /* Tell the scheduler how much we idled: */