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Zephyr,power-state clarify min-residency-us and remove incoherent "consistency" check which was not consistent #97108

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Merged
merged 2 commits into from
Oct 9, 2025
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Zephyr,power-state clarify min-residency-us and remove incoherent "consistency" check which was not consistent #97108

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ccd582b
dts: bindings: zephyr,power-state: Clarify min-residency-us
decsny Oct 7, 2025
3b68396
pm: Remove "power state consistency" check
decsny Oct 7, 2025
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14 changes: 10 additions & 4 deletions dts/bindings/power/zephyr,power-state.yaml
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Original file line number Diff line number Diff line change
@@ -1,7 +1,9 @@
# Copyright (c) 2020, Intel Corporation
# Copyright 2025 NXP
# SPDX-License-Identifier: Apache-2.0

description: Properties for power management state
description: |
Properties for power management idle states.

compatible: "zephyr,power-state"

Expand All @@ -24,9 +26,13 @@ properties:
min-residency-us:
type: int
description: |
Minimum residency duration in microseconds. It is the minimum time for a
given idle state to be worthwhile energywise. It includes the time to enter
in this state.
Minimum residency duration in microseconds.

How much time the residency in a given idle state must last for state entry
to be worthwhile energywise. It includes the time to enter into this state
and represents the "break-even" time to justify the time and power spent
on the work needed for entering and exiting the state based on how much actual energy
is saved once in the state, compared to choosing the next shallowest state.
exit-latency-us:
type: int
description: |
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28 changes: 0 additions & 28 deletions subsys/pm/state.c
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Expand Up @@ -11,34 +11,6 @@
BUILD_ASSERT(DT_NODE_EXISTS(DT_PATH(cpus)),
"cpus node not defined in Devicetree");

/**
* Check CPU power state consistency.
*
* @param i Power state index.
* @param node_id CPU node identifier.
*/
#define CHECK_POWER_STATE_CONSISTENCY(i, node_id) \
BUILD_ASSERT( \
DT_PROP_BY_PHANDLE_IDX_OR(node_id, cpu_power_states, i, \
min_residency_us, 0U) >= \
DT_PROP_BY_PHANDLE_IDX_OR(node_id, cpu_power_states, i, \
exit_latency_us, 0U), \
"Found CPU power state with min_residency < exit_latency")

/**
* @brief Check CPU power states consistency
*
* All states should have a minimum residency >= than the exit latency.
*
* @param node_id A CPU node identifier.
*/
#define CHECK_POWER_STATES_CONSISTENCY(node_id) \
LISTIFY(DT_PROP_LEN_OR(node_id, cpu_power_states, 0), \
CHECK_POWER_STATE_CONSISTENCY, (;), node_id); \

/* Check that all power states are consistent */
DT_FOREACH_CHILD(DT_PATH(cpus), CHECK_POWER_STATES_CONSISTENCY)

#define DEFINE_CPU_STATES(n) \
static const struct pm_state_info pmstates_##n[] \
= PM_STATE_INFO_LIST_FROM_DT_CPU(n);
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