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| author |   Daniel Lezcano <daniel.lezcano@linaro.org> | 2020-12-15 00:38:04 +0100 |
|---|---|---|
| committer | Daniel Lezcano <daniel.lezcano@linaro.org> | 2021-01-19 22:22:45 +0100 |
| commit | a7d6ba14efb778fc8c65c627a057d5dd29debd04 (patch) | |
| tree | 17d8de4f98499479bbeac934a4668f745087d9bc /Documentation/driver-api | |
| parent | thermal/core: Remove notify ops (diff) | |
| download | linux-dev-a7d6ba14efb778fc8c65c627a057d5dd29debd04.tar.xz linux-dev-a7d6ba14efb778fc8c65c627a057d5dd29debd04.zip | |
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.rst | 13 |
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 |