mcpm_wait_for_cpu_powerdown(9)

📦 version 7.3.1, in nixpkgs unstable

💖 mcpm_wait_for_cpu_powerdown(9) 💖

okay so bestie, welcome to the Kernel API Manual — this one's about mcpm_wait_for_cpu_powerdown, and it does exactly what it says on the tin: it waits for a specified CPU to halt, and makes sure it is powered off. no cap. 🎀

✨ NAME ✨

mcpm_wait_for_cpu_powerdown — wait for a specified CPU to halt, and make sure it is powered off 🫶

🌸 SYNOPSIS 🌸

int mcpm_wait_for_cpu_powerdown (unsigned int cpu , unsigned int cluster );

like, that's the whole vibe. two args, one int back. 💅

🦋 ARGUMENTS 🦋

  • cpu — the CPU number, within the given cluster. yes, within the cluster, bestie, don't come at me with a global CPU number. 🙈
  • cluster — the cluster number for that CPU. it's giving "which friend group is this CPU in" energy. 👑

💜 DESCRIPTION 💜

so here's the tea ☕ — you call this function to make sure that a pending powerdown has actually taken effect, and that the CPU is safely parked, before you go doing non-mcpm operations that may affect that CPU. the example the page gives is kexec trashing the kernel text — which, yeah, that's a whole situation. 💀

real talk: it is *not* necessary to call this function if all you need is to serialise a pending powerdown with mcpm_cpu_power_up or a wakeup event. so don't be extra for no reason. 😌
do NOT call this function unless the specified CPU has already called mcpm_cpu_power_down or has committed to doing so. like, fr fr, don't skip that part. 🚨

⭐ RETURN ⭐

  • zero if the CPU is in a safely parked state 🅿️✨
  • nonzero otherwise (e.g., timeout) 😭

🌈 SEE ALSO 🌈

kernel file ./arch/arm/include/asm/mcpm.h — and honestly the whole mcpm friend group:

and that's the page, bestie 🧚💖 — brought to you by ./arch/arm/include/asm, October 2026, and this absolute icon of a manpage, mcpm_wait_for_cpu_powerdown(9). periodt. 💅🎀

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