Commit 04bf1fe4 authored by Thierry Reding's avatar Thierry Reding Committed by Daniel Lezcano
Browse files

thermal: Allow selecting the bang-bang governor as default 



For many setups the bang-bang governor is exactly what we want. Many
ARM SoC-based devices use fans to cool down the entire SoC and that
works well only with the bang-bang governor because it uses the
hysteresis in order to let the fan run for a while to cool the SoC
down below the trip point before switching it off again.

The step-wise governor will behave strangely in these situations. It
doesn't use the hysteresis, so it can lead to situations where the fan
is turned on for only a very brief period and then is switched back off,
only to get switched back on again very quickly because the SoC hasn't
cooled down very much.

Signed-off-by: default avatarThierry Reding <treding@nvidia.com>
Link: https://lore.kernel.org/r/20230609124408.3788680-1-thierry.reding@gmail.com


Signed-off-by: default avatarDaniel Lezcano <daniel.lezcano@linaro.org>
parent 598e1afc

drivers/thermal/Kconfig

+8 −0
Original line number Diff line number Diff line
@@ -130,6 +130,14 @@ config THERMAL_DEFAULT_GOV_POWER_ALLOCATOR 
	  system and device power allocation. This governor can only

	  operate on cooling devices that implement the power API.



config THERMAL_DEFAULT_GOV_BANG_BANG

	bool "bang_bang"

	depends on THERMAL_GOV_BANG_BANG

	help

	  Use the bang_bang governor as default. This throttles the

	  devices one step at the time, taking into account the trip

	  point hysteresis.



endchoice



config THERMAL_GOV_FAIR_SHARE

drivers/thermal/thermal_core.h

+2 −0
Original line number Diff line number Diff line
@@ -23,6 +23,8 @@ 
#define DEFAULT_THERMAL_GOVERNOR       "user_space"

#elif defined(CONFIG_THERMAL_DEFAULT_GOV_POWER_ALLOCATOR)

#define DEFAULT_THERMAL_GOVERNOR       "power_allocator"

#elif defined(CONFIG_THERMAL_DEFAULT_GOV_BANG_BANG)

#define DEFAULT_THERMAL_GOVERNOR       "bang_bang"

#endif



/* Initial state of a cooling device during binding */