Merge tag 'for-linus' of git://git.kernel.org/pub/scm/virt/kvm/kvm

[linux-2.6-microblaze.git] / drivers / idle / intel_idle.c

diff --git a/drivers/idle/intel_idle.c b/drivers/idle/intel_idle.c
index 9a810e4..01bace4 100644 (file)
--- a/drivers/idle/intel_idle.c
+++ b/drivers/idle/intel_idle.c
@@ -8,7 +8,7 @@
  */
 
 /*
- * intel_idle is a cpuidle driver that loads on specific Intel processors
+ * intel_idle is a cpuidle driver that loads on all Intel CPUs with MWAIT
  * in lieu of the legacy ACPI processor_idle driver.  The intent is to
  * make Linux more efficient on these processors, as intel_idle knows
  * more than ACPI, as well as make Linux more immune to ACPI BIOS bugs.
@@ -20,7 +20,11 @@
  * All CPUs have same idle states as boot CPU
  *
  * Chipset BM_STS (bus master status) bit is a NOP
- *     for preventing entry into deep C-stats
+ *     for preventing entry into deep C-states
+ *
+ * CPU will flush caches as needed when entering a C-state via MWAIT
+ *     (in contrast to entering ACPI C3, in which case the WBINVD
+ *     instruction needs to be executed to flush the caches)
  */
 
 /*
@@ -1212,14 +1216,13 @@ static bool __init intel_idle_acpi_cst_extract(void)
                if (!intel_idle_cst_usable())
                        continue;
 
-               if (!acpi_processor_claim_cst_control()) {
-                       acpi_state_table.count = 0;
-                       return false;
-               }
+               if (!acpi_processor_claim_cst_control())
+                       break;
 
                return true;
        }
 
+       acpi_state_table.count = 0;
        pr_debug("ACPI _CST not found or not usable\n");
        return false;
 }
@@ -1236,7 +1239,7 @@ static void __init intel_idle_init_cstates_acpi(struct cpuidle_driver *drv)
                struct acpi_processor_cx *cx;
                struct cpuidle_state *state;
 
-               if (intel_idle_max_cstate_reached(cstate))
+               if (intel_idle_max_cstate_reached(cstate - 1))
                        break;
 
                cx = &acpi_state_table.states[cstate];