1 files changed, 26 insertions, 6 deletions

diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c
index 7acb32e7f817..4a5c4a44ffb1 100644
--- a/drivers/idle/intel_idle.c
+++ b/drivers/idle/intel_idle.c
@@ -62,6 +62,7 @@
 #include <linux/notifier.h>
 #include <linux/cpu.h>
 #include <asm/mwait.h>
+#include <asm/msr.h>
 
 #define INTEL_IDLE_VERSION "0.4"
 #define PREFIX "intel_idle: "
@@ -85,6 +86,12 @@ static int intel_idle(struct cpuidle_device *dev, struct cpuidle_state *state);
 static struct cpuidle_state *cpuidle_state_table;
 
 /*
+ * Hardware C-state auto-demotion may not always be optimal.
+ * Indicate which enable bits to clear here.
+ */
+static unsigned long long auto_demotion_disable_flags;
+
+/*
  * Set this flag for states where the HW flushes the TLB for us
  * and so we don't need cross-calls to keep it consistent.
  * If this flag is set, SW flushes the TLB, so even if the
@@ -263,7 +270,7 @@ static void __setup_broadcast_timer(void *arg)
         clockevents_notify(reason, &cpu);
 }
 
-static int __cpuinit setup_broadcast_cpuhp_notify(struct notifier_block *n,
+static int setup_broadcast_cpuhp_notify(struct notifier_block *n,
                 unsigned long action, void *hcpu)
 {
         int hotcpu = (unsigned long)hcpu;
@@ -273,18 +280,23 @@ static int __cpuinit setup_broadcast_cpuhp_notify(struct notifier_block *n,
                 smp_call_function_single(hotcpu, __setup_broadcast_timer,
                         (void *)true, 1);
                 break;
-        case CPU_DOWN_PREPARE:
-                smp_call_function_single(hotcpu, __setup_broadcast_timer,
-                        (void *)false, 1);
-                break;
         }
         return NOTIFY_OK;
 }
 
-static struct notifier_block __cpuinitdata setup_broadcast_notifier = {
+static struct notifier_block setup_broadcast_notifier = {
         .notifier_call = setup_broadcast_cpuhp_notify,
 };
 
+static void auto_demotion_disable(void *dummy)
+{
+        unsigned long long msr_bits;
+
+        rdmsrl(MSR_NHM_SNB_PKG_CST_CFG_CTL, msr_bits);
+        msr_bits &= ~auto_demotion_disable_flags;
+        wrmsrl(MSR_NHM_SNB_PKG_CST_CFG_CTL, msr_bits);
+}
+
 /*
  * intel_idle_probe()
  */
@@ -328,11 +340,17 @@ static int intel_idle_probe(void)
         case 0x25:      /* Westmere */
         case 0x2C:      /* Westmere */
                 cpuidle_state_table = nehalem_cstates;
+                auto_demotion_disable_flags =
+                        (NHM_C1_AUTO_DEMOTE | NHM_C3_AUTO_DEMOTE);
                 break;
 
         case 0x1C:      /* 28 - Atom Processor */
+                cpuidle_state_table = atom_cstates;
+                break;
+
         case 0x26:      /* 38 - Lincroft Atom Processor */
                 cpuidle_state_table = atom_cstates;
+                auto_demotion_disable_flags = ATM_LNC_C6_AUTO_DEMOTE;
                 break;
 
         case 0x2A:      /* SNB */
@@ -440,6 +458,8 @@ static int intel_idle_cpuidle_devices_init(void)
                         return -EIO;
                 }
         }
+        if (auto_demotion_disable_flags)
+                smp_call_function(auto_demotion_disable, NULL, 1);
 
         return 0;
 }