kernel.git/drivers/thermal/gov_power_allocator.c, branch linux-6.9.y

thermal: gov_power_allocator: Allow binding without trip points

2024-04-03T14:32:15Z

IPA probe function was recently refactored to perform extra error checks and make sure the thermal zone has trip points necessary for the IPA operation. With this change, if a thermal zone is probed such that it has no trip points that IPA can use, IPA will fail and the TZ won't be created. This is the case if a platform defines a TZ without cooling devices and only with "hot"/"critical" trip points, often found on some Qualcomm devices [1]. Documentation across IPA code (notably get_governor_trips() kerneldoc) suggests that IPA is supposed to handle such TZ even if it won't actually do anything. This commit partially reverts the previous change to allow IPA to bind to such "empty" thermal zones. Fixes: e83747c2f8e3 ("thermal: gov_power_allocator: Set up trip points earlier") Link: arch/arm64/boot/dts/qcom/sc7180.dtsi#n4776 # [1] Signed-off-by: Nikita Travkin Reviewed-by: Lukasz Luba Signed-off-by: Rafael J. Wysocki

thermal: gov_power_allocator: Allow binding without cooling devices

2024-04-03T14:32:14Z

IPA was recently refactored to split out memory allocation into a separate funciton. That funciton was made to return -EINVAL if there is zero power_actors and thus no memory to allocate. This causes IPA to fail probing when the thermal zone has no attached cooling devices. Since cooling devices can attach after the thermal zone is created and the governer is attached to it, failing probe due to the lack of cooling devices is incorrect. Change the allocate_actors_buffer() to return success when there is no cooling devices present. Fixes: 912e97c67cc3 ("thermal: gov_power_allocator: Move memory allocation out of throttle()") Signed-off-by: Nikita Travkin Reviewed-by: Lukasz Luba Signed-off-by: Rafael J. Wysocki

thermal: gov_power_allocator: Avoid overwriting PID coefficients from setup time

2024-02-12T13:13:36Z

When the PID coefficients k_* are set via sysfs before the IPA algorithm is triggered then the coefficients would be overwritten after IPA throttle() is called. The old configuration values might be different than the new values estimated by the IPA internal algorithm. There might be a time delay when this overwriting happens. It depends on the thermal zone temperature value. The temperature value needs to cross the first trip point value then IPA algorithms start operating. Although, the PID coefficients setup time should not be affected or linked to any later operating phase and values must not be overwritten. This patch initializes params->sustainable_power when the governor binds to thermal zone to avoid overwriting k_*. The basic function won't be affected, as the k_* still can be estimated if the sustainable_power is modified. Signed-off-by: Di Shen Reviewed-by: Lukasz Luba Signed-off-by: Rafael J. Wysocki

thermal: gov_power_allocator: avoid inability to reset a cdev

2024-01-12T14:38:23Z

Commit 0952177f2a1f ("thermal/core/power_allocator: Update once cooling devices when temp is low") adds an update flag to avoid triggering a thermal event when there is no need, and the thermal cdev is updated once when the temperature is low. But when the trips are writable, and switch_on_temp is set to be a higher value, the cooling device state may not be reset to 0, because last_temperature is smaller than switch_on_temp. For example: First: switch_on_temp=70 control_temp=85; Then userspace change the trip_temp: switch_on_temp=45 control_temp=55 cur_temp=54 Then userspace reset the trip_temp: switch_on_temp=70 control_temp=85 cur_temp=57 last_temp=54 At this time, the cooling device state should be reset to 0. However, because cur_temp(57) < switch_on_temp(70) last_temp(54) < switch_on_temp(70) ----> update = false, update is false, the cooling device state can not be reset. Using the observation that tz->passive can also be regarded as the temperature status, set the update flag to the tz->passive value. When the temperature drops below switch_on for the first time, the states of cooling devices can be reset once, and tz->passive is updated to 0. In the next round, because tz->passive is 0, cdev->state will not be updated. By using the tz->passive value as the "update" flag, the issue above can be solved, and the cooling devices can be updated only once when the temperature is low. Fixes: 0952177f2a1f ("thermal/core/power_allocator: Update once cooling devices when temp is low") Cc: 5.13+ # 5.13+ Suggested-by: Wei Wang Signed-off-by: Di Shen Reviewed-by: Lukasz Luba [ rjw: Subject and changelog edits ] Signed-off-by: Rafael J. Wysocki

thermal: gov_power_allocator: Support new update callback of weights

2023-12-29T17:01:01Z

When the thermal instance's weight is updated from the sysfs the governor update_tz() callback is triggered. Implement proper reaction to this event in the IPA, which would save CPU cycles spent in throttle(). This will speed-up the main throttle() IPA function and clean it up a bit. Signed-off-by: Lukasz Luba Signed-off-by: Rafael J. Wysocki

thermal: gov_power_allocator: Simplify checks for valid power actor

2023-12-29T17:01:00Z

There is a need to check if the cooling device in the thermal zone supports IPA callback and is set for control trip point. Refactor the code which validates the power actor capabilities and make it more consistent in all places. No intentional functional impact. Signed-off-by: Lukasz Luba Signed-off-by: Rafael J. Wysocki

thermal: gov_power_allocator: Move memory allocation out of throttle()

2023-12-29T17:01:00Z

The new thermal callback allows to react to the change of cooling instances in the thermal zone. Move the memory allocation to that new callback and save CPU cycles in the throttle() code path. Signed-off-by: Lukasz Luba Signed-off-by: Rafael J. Wysocki

thermal: gov_power_allocator: Change trace functions

2023-12-29T17:01:00Z

Change trace event trace_thermal_power_allocator() to not use dynamic array for requested power and granted power for all power actors. Instead, simplify the trace event and print other simple values. Add new trace event to print power actor information of requested power and granted power. That trace event would be called in a loop for each power actor. The trace data would be easier to parse comparing to the dynamic array implementation. Signed-off-by: Lukasz Luba Signed-off-by: Rafael J. Wysocki

thermal: gov_power_allocator: Refactor checks in divvy_up_power()

2023-12-29T17:01:00Z

Simplify the code and remove one extra 'if' block. No intentional functional impact. Signed-off-by: Lukasz Luba Signed-off-by: Rafael J. Wysocki

thermal: gov_power_allocator: Refactor check_power_actors()

2023-12-29T17:01:00Z

In preparation for a subsequent change, rearrange check_power_actors(). No intentional functional impact. Signed-off-by: Lukasz Luba Signed-off-by: Rafael J. Wysocki