ACPI, cpuidle: Clarify C-state description in sysfs

Add a new sysfs entry under cpuidle states. desc - can be used by driver to
communicate to userspace any specific information about the state.
This helps in identifying the exact hardware C-states behind the ACPI C-state
definition.

Idea is to export this through powertop, which will help to map the C-state
reported by powertop to actual hardware C-state.

Signed-off-by: Venkatesh Pallipadi <venkatesh.pallipadi@intel.com>
Signed-off-by: Len Brown <len.brown@intel.com>

1 files changed, 2 insertions, 0 deletions

diff --git a/include/linux/cpuidle.h b/include/linux/cpuidle.h
index 385d45b616db..6b72a4584086 100644
--- a/include/linux/cpuidle.h
+++ b/include/linux/cpuidle.h
@@ -19,6 +19,7 @@
 
 #define CPUIDLE_STATE_MAX       8
 #define CPUIDLE_NAME_LEN        16
+#define CPUIDLE_DESC_LEN        32
 
 struct cpuidle_device;
 
@@ -29,6 +30,7 @@ struct cpuidle_device;
 
 struct cpuidle_state {
         char            name[CPUIDLE_NAME_LEN];
+        char            desc[CPUIDLE_DESC_LEN];
         void            *driver_data;
 
         unsigned int    flags;