diff options
| author | Rafael J. Wysocki <rafael.j.wysocki@intel.com> | 2014-05-01 00:14:04 +0200 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@linuxfoundation.org> | 2015-08-03 09:29:51 -0700 |
| commit | dff5d6ed2aa052706a6cb877aa27f4c6b9e70f05 (patch) | |
| tree | 35f0ce84b5c05dd182d22f3c685f96d7f573bd6f /drivers/cpuidle | |
| parent | 2fee157bdb44fde593a541ba0268c742a70d32e9 (diff) | |
| download | lwn-dff5d6ed2aa052706a6cb877aa27f4c6b9e70f05.tar.gz lwn-dff5d6ed2aa052706a6cb877aa27f4c6b9e70f05.zip | |
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 <rafael.j.wysocki@intel.com>
[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@linux.vnet.ibm.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/cpuidle')
| -rw-r--r-- | drivers/cpuidle/cpuidle.c | 3 | ||||
| -rw-r--r-- | drivers/cpuidle/governors/menu.c | 2 |
2 files changed, 4 insertions, 1 deletions
diff --git a/drivers/cpuidle/cpuidle.c b/drivers/cpuidle/cpuidle.c index e3d2052e7552..1adc039fe74d 100644 --- a/drivers/cpuidle/cpuidle.c +++ b/drivers/cpuidle/cpuidle.c @@ -131,6 +131,9 @@ 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 */ |