From: Rafael J. Wysocki Date: Wed, 30 Apr 2014 22:14:04 +0000 (+0200) Subject: cpuidle / menu: Return (-1) if there are no suitable states X-Git-Tag: v3.12.45~19 X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=4d8b8587b1f7d846e05df01d4c1ad3ff93cd5846;p=thirdparty%2Fkernel%2Fstable.git cpuidle / menu: Return (-1) if there are no suitable states 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 [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 Signed-off-by: Jiri Slaby --- diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c index 22c07fb6ab785..ef44248a5c378 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 cf7f2f0e4ef54..027c484e1ec93 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 */