cpuidle / menu: Return (-1) if there are no suitable states

If there is a PM QoS latency limit and all of the sufficiently shallow
C-states are disabled, the cpuidle menu governor returns 0 which on
some systems is CPUIDLE_DRIVER_STATE_START and shouldn't be returned
if that C-state has been disabled.

Fix the issue by modifying the menu governor to return (-1) in such
situations.

Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>

diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
index 71b52329335472b7a888e16b4075c6ea7a4f58c5..3ca15a8cbaa884f5a80bb06c7c6583121651814e 100644 (file)
--- a/drivers/cpuidle/governors/menu.c
+++ b/drivers/cpuidle/governors/menu.c
@@ -296,7 +296,7 @@ static int menu_select(struct cpuidle_driver *drv, struct cpuidle_device *dev)
                data->needs_update = 0;
        }
 
-       data->last_state_idx = 0;
+       data->last_state_idx = CPUIDLE_DRIVER_STATE_START - 1;
 
        /* Special case when user has set very strict latency requirement */
        if (unlikely(latency_req == 0))