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, 6 insertions, 3 deletions

diff --git a/include/acpi/processor.h b/include/acpi/processor.h
index cdc8004cfd12..06480bcabfdc 100644
--- a/include/acpi/processor.h
+++ b/include/acpi/processor.h
@@ -32,9 +32,11 @@
 #define DOMAIN_COORD_TYPE_SW_ANY        0xfd
 #define DOMAIN_COORD_TYPE_HW_ALL        0xfe
 
-#define ACPI_CSTATE_SYSTEMIO    (0)
-#define ACPI_CSTATE_FFH         (1)
-#define ACPI_CSTATE_HALT        (2)
+#define ACPI_CSTATE_SYSTEMIO    0
+#define ACPI_CSTATE_FFH         1
+#define ACPI_CSTATE_HALT        2
+
+#define ACPI_CX_DESC_LEN        32
 
 /* Power Management */
 
@@ -74,6 +76,7 @@ struct acpi_processor_cx {
         u64 time;
         struct acpi_processor_cx_policy promotion;
         struct acpi_processor_cx_policy demotion;
+        char desc[ACPI_CX_DESC_LEN];
 };
 
 struct acpi_processor_power {