cpu_cluster_pm_enter(9)

✨ cpu_cluster_pm_enter(9) ✨

okay so this is a page from the Kernel API Manual and honestly? it's kind of a big deal. bestie, we're talking about cpu_cluster_pm_enter — the CPU cluster low power entry notifier. 💅

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🎀 NAME 🎀

cpu_cluster_pm_enter — the CPU cluster low power entry notifier. that's it, that's the vibe. 🦋

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🌸 SYNOPSIS 🌸

int cpu_cluster_pm_enter (void );

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✨ ARGUMENTS ✨

• void — no arguments. nothing. zero. she takes nothing and she gives everything. 🫶

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💖 DESCRIPTION 💖

so what she does is notify all the listeners that every single cpu in a power domain is heading into a low power state — and heads up, that state might cause some of the blocks in that same power domain to reset. 😭 lowkey stressful but that's the assignment.

here's the timing, and it's strict, no cap:

• you must call this after cpu_pm_enter has been called on all cpus in the power domain, and
• before cpu_pm_exit has been called on any cpu in the power domain.

the drivers getting notified can include the VFP co-processor, the interrupt controller and its PM extensions, and local CPU timers doing context save/restore — all stuff that genuinely shouldn't be interrupted. so yeah, hence it must be called with interrupts disabled. 🔥

Must be called with interrupts disabled. (yes, again. she's serious. this is not a drill, bestie. 🚨)

return conditions are the same as __raw_notifier_call_chain. iykyk. ⭐

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🧚 SEE ALSO 🧚

• Kernel file ./kernel/cpu_pm.c
• cpu_pm_register_notifier(9)
• cpu_pm_unregister_notifier(9)
• cpu_pm_enter(9)
• cpu_pm_exit(9)
• cpu_cluster_pm_exit(9)

go read those too, they're the whole friend group. 👑

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and that's the page!! 🍓 this iconic little number lives in ./kernel and it's dated October 2026 — yes, from the future, main character energy fr fr. bye bestie, stay interrupt-disabled 💜🎀