From 9b0e6e22762be47e0177b85cea7d4b0b461731f1 Mon Sep 17 00:00:00 2001 From: "Rafael J. Wysocki" Date: Thu, 1 May 2014 00:14:04 +0200 Subject: [PATCH] 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: Greg Kroah-Hartman --- 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 2394b188121..cffecb33a23 100644 --- a/drivers/cpuidle/cpuidle.c +++ b/drivers/cpuidle/cpuidle.c @@ -140,6 +140,9 @@ 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 e7156fb41b7..afbe842fd1a 100644 --- a/drivers/cpuidle/governors/menu.c +++ b/drivers/cpuidle/governors/menu.c @@ -280,7 +280,7 @@ 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 */ -- 2.20.1