From: "Rafael J. Wysocki" <rafael.j.wysocki@xxxxxxxxx>
This patch has been added to the 3.12 stable tree. If you have any
objections, please let us know.
===============
commit 3836785a1bdcd6706c68ad46bf53adc0b057b310 upstream.
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@xxxxxxxxx>
[shilpab: Backport to 3.10.y
- adjust context
- add a check if 'next_state' is less than 0 in 'cpuidle_idle_call()',
this ensures that we exit 'cpuidle_idle_call()' if governor->select()
returns negative value]
Signed-off-by: Shilpasri G Bhat <shilpa.bhat@xxxxxxxxxxxxxxxxxx>
Signed-off-by: Jiri Slaby <jslaby@xxxxxxx>
---
drivers/cpuidle/cpuidle.c | 3 +++
drivers/cpuidle/governors/menu.c | 2 +-
2 files changed, 4 insertions(+), 1 deletion(-)
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c
index 22c07fb6ab78..ef44248a5c37 100644
--- a/drivers/cpuidle/cpuidle.c
+++ b/drivers/cpuidle/cpuidle.c
@@ -133,6 +133,9 @@ int cpuidle_idle_call(void)
/* ask the governor for the next state */
next_state = cpuidle_curr_governor->select(drv, dev);
+ if (next_state < 0)
+ return -EBUSY;
+
if (need_resched()) {
dev->last_residency = 0;
/* give the governor an opportunity to reflect on the outcome */
diff --git a/drivers/cpuidle/governors/menu.c b/drivers/cpuidle/governors/menu.c
index cf7f2f0e4ef5..027c484e1ec9 100644
--- a/drivers/cpuidle/governors/menu.c
+++ b/drivers/cpuidle/governors/menu.c
@@ -297,7 +297,7 @@ 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;
data->exit_us = 0;
/* Special case when user has set very strict latency requirement */
--
2.4.6
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