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authorDaniel Lezcano <daniel.lezcano@linaro.org>2020-12-15 00:38:04 +0100
committerDaniel Lezcano <daniel.lezcano@linaro.org>2021-01-19 22:22:45 +0100
commita7d6ba14efb778fc8c65c627a057d5dd29debd04 (patch)
tree17d8de4f98499479bbeac934a4668f745087d9bc /Documentation/driver-api
parent04f111130e9afa41c10d7bcec14e00e3be8b6977 (diff)
downloadlinux-a7d6ba14efb778fc8c65c627a057d5dd29debd04.tar.gz
thermal/core: Remove the 'forced_passive' option
The code was reorganized in 2012 with the commit 0c01ebbfd3caf1. The main change is a loop on the trip points array and a unconditional call to the throttle() ops of the governors for each of them even if the trip temperature is not reached yet. With this change, the 'forced_passive' is no longer checked in the thermal_zone_device_update() function but in the step wise governor's throttle() callback. As the force_passive does no belong to the trip point array, the thermal_zone_device_update() can not compare with the specified passive temperature, thus does not detect the passive limit has been crossed. Consequently, throttle() is never called and the 'forced_passive' branch is unreached. In addition, the default processor cooling device is not automatically bound to the thermal zone if there is not passive trip point, thus the 'forced_passive' can not operate. If there is an active trip point, then the throttle function will be called to mitigate at this temperature and the 'forced_passive' will override the mitigation of the active trip point in this case but with the default cooling device bound to the thermal zone, so usually a fan, and that is not a passive cooling effect. Given the regression exists since more than 8 years, nobody complained and at the best of my knowledge there is no bug open in https://bugzilla.kernel.org, it is reasonable to say it is unused. Remove the 'forced_passive' related code. Signed-off-by: Daniel Lezcano <daniel.lezcano@linaro.org> Reviewed-by: Thara Gopinath <thara.gopinath@linaro.org> Link: https://lore.kernel.org/r/20201214233811.485669-1-daniel.lezcano@linaro.org
Diffstat (limited to 'Documentation/driver-api')
-rw-r--r--Documentation/driver-api/thermal/sysfs-api.rst13
1 files changed, 0 insertions, 13 deletions
diff --git a/Documentation/driver-api/thermal/sysfs-api.rst b/Documentation/driver-api/thermal/sysfs-api.rst
index e7520cb439ac..a4969c474cc3 100644
--- a/Documentation/driver-api/thermal/sysfs-api.rst
+++ b/Documentation/driver-api/thermal/sysfs-api.rst
@@ -520,19 +520,6 @@ available_policies
RW, Optional
-passive
- Attribute is only present for zones in which the passive cooling
- policy is not supported by native thermal driver. Default is zero
- and can be set to a temperature (in millidegrees) to enable a
- passive trip point for the zone. Activation is done by polling with
- an interval of 1 second.
-
- Unit: millidegrees Celsius
-
- Valid values: 0 (disabled) or greater than 1000
-
- RW, Optional
-
emul_temp
Interface to set the emulated temperature method in thermal zone
(sensor). After setting this temperature, the thermal zone may pass