linux/drivers/cpuidle
Rafael J. Wysocki 0cc2b4e5a0 PM / QoS: Fix device resume latency PM QoS
The special value of 0 for device resume latency PM QoS means
"no restriction", but there are two problems with that.

First, device resume latency PM QoS requests with 0 as the
value are always put in front of requests with positive
values in the priority lists used internally by the PM QoS
framework, causing 0 to be chosen as an effective constraint
value.  However, that 0 is then interpreted as "no restriction"
effectively overriding the other requests with specific
restrictions which is incorrect.

Second, the users of device resume latency PM QoS have no
way to specify that *any* resume latency at all should be
avoided, which is an artificial limitation in general.

To address these issues, modify device resume latency PM QoS to
use S32_MAX as the "no constraint" value and 0 as the "no
latency at all" one and rework its users (the cpuidle menu
governor, the genpd QoS governor and the runtime PM framework)
to follow these changes.

Also add a special "n/a" value to the corresponding user space I/F
to allow user space to indicate that it cannot accept any resume
latencies at all for the given device.

Fixes: 85dc0b8a40 (PM / QoS: Make it possible to expose PM QoS latency constraints)
Link: https://bugzilla.kernel.org/show_bug.cgi?id=197323
Reported-by: Reinette Chatre <reinette.chatre@intel.com>
Tested-by: Reinette Chatre <reinette.chatre@intel.com>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
Acked-by: Alex Shi <alex.shi@linaro.org>
Cc: All applicable <stable@vger.kernel.org>
2017-10-24 15:20:45 +02:00
..
governors PM / QoS: Fix device resume latency PM QoS 2017-10-24 15:20:45 +02:00
coupled.c smp: Avoid using two cache lines for struct call_single_data 2017-08-29 15:14:38 +02:00
cpuidle-arm.c ARM: cpuidle: Avoid memleak if init fail 2017-09-19 23:10:51 +02:00
cpuidle-at91.c drivers/cpuidle: Convert non-modular drivers to use builtin_platform_driver 2015-06-16 14:12:38 -04:00
cpuidle-big_little.c ARM: MCPM: remove residency argument from mcpm_cpu_suspend() 2015-05-06 11:47:10 -04:00
cpuidle-calxeda.c ARM: migrate to common PSCI client code 2015-08-03 15:38:39 +01:00
cpuidle-clps711x.c drivers/cpuidle: make cpuidle-clps711x.c explicitly non-modular 2015-12-15 00:22:21 +01:00
cpuidle-cps.c MIPS: Unify checks for sibling CPUs 2017-08-30 00:57:27 +02:00
cpuidle-exynos.c drivers/cpuidle: make cpuidle-exynos.c explicitly non-modular 2015-12-15 00:22:22 +01:00
cpuidle-kirkwood.c ARM: cpuidle: Remove duplicate header inclusion 2015-03-23 18:03:11 +01:00
cpuidle-mvebu-v7.c cpuidle: mvebu: disable the bind/unbind attributes and use builtin_platform_driver 2015-10-23 12:40:48 +02:00
cpuidle-powernv.c powerpc/powernv/idle: Disable LOSE_FULL_CONTEXT states when stop-api fails 2017-08-08 20:21:23 +10:00
cpuidle-pseries.c cpuidle: powerpc: no memory barrier after break from idle 2017-06-28 13:08:12 +10:00
cpuidle-ux500.c drivers/cpuidle: make cpuidle-ux500.c explicitly non-modular 2015-12-15 00:22:22 +01:00
cpuidle-zynq.c drivers/cpuidle: Convert non-modular drivers to use builtin_platform_driver 2015-06-16 14:12:38 -04:00
cpuidle.c PM / s2idle: Rename ->enter_freeze to ->enter_s2idle 2017-08-11 01:29:56 +02:00
cpuidle.h cpuidle/coupled: Add sanity check for safe_state_index 2015-09-03 03:05:47 +02:00
driver.c cpuidle: Make drivers initialize polling state 2017-08-30 03:06:33 +02:00
dt_idle_states.c Merge branch 'pm-sleep' 2017-09-04 00:06:02 +02:00
dt_idle_states.h drivers: cpuidle: implement DT based idle states infrastructure 2014-09-25 10:52:20 +02:00
governor.c cpuidle: governors: Remove remaining old module code 2016-10-21 14:49:51 +02:00
Kconfig cpuidle: Don't enable all governors by default 2016-01-15 22:39:58 +01:00
Kconfig.arm ARM: cpuidle: Support asymmetric idle definition 2017-06-24 01:51:00 +02:00
Kconfig.mips cpuidle: cpuidle-cps: Enable use with MIPSr6 CPUs. 2016-10-04 16:13:57 +02:00
Kconfig.powerpc
Makefile cpuidle: Move polling state initialization code to separate file 2017-08-30 03:06:27 +02:00
poll_state.c cpuidle: Make drivers initialize polling state 2017-08-30 03:06:33 +02:00
sysfs.c cpuidle: Validate cpu_dev in cpuidle_add_sysfs() 2017-03-21 22:26:37 +01:00