STRUCT DEV_PM_DOMAIN(9)

💅 struct dev_pm_domain(9) — aka the kernel API manual, but make it make sense 🎀

okay bestie, so this one's from the kernel API manual and it's literally all about struct dev_pm_domain — the power management domain representation. yes, that's a whole thing and yes, you're gonna get it. sit down, hydrate, let's go ✨

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🌸 NAME 🌸

struct dev_pm_domain — power management domain representation. that's it, that's the vibe. it's a struct that represents a PM domain. periodt 💅

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🦋 SYNOPSIS 🦋

like, this is the shape of it, no cap. copy it exactly how it is, don't freestyle:

struct dev_pm_domain {
    struct dev_pm_ops       ops;
    int (*start)(struct device *dev);
    void (*detach)(struct device *dev, bool power_off);
    int (*activate)(struct device *dev);
    void (*sync)(struct device *dev);
    void (*dismiss)(struct device *dev);
    int (*set_performance_state)(struct device *dev, unsigned int state);
};

look at all those function pointers. she's got range 👑

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✨ Members ✨

okay so here's the cast of characters, and honestly each one is a main character in their own right:

• ops — the power management operations tied to this domain. the whole ops situation. it's giving struct dev_pm_ops energy, iykyk 🫶
• start — gets called when a user needs to start the device via the domain. like, the user wants the device going, and the domain handles the starting. iconic.
• detach — called when you're removing a device from the domain. bye bestie 👋 it takes struct device *dev and a bool power_off, so it knows which device and whether to power it off.
• activate — this one fires before the probe routines run for bus types and drivers. so it's the pre-game. the warm-up. the hype moment before the actual probe 🎀
• sync — called after a successful driver probe. so the probe said slay and then sync shows up to align everything. 💖
• dismiss — called after an unsuccessful driver probe, and also after driver removal. so when things don't work out, or when the driver leaves, dismiss is there. 😭 nothing but respect for her.
• set_performance_state — called to request a new performance state. signature is int (*set_performance_state)(struct device *dev, unsigned int state); — you pass the device and the unsigned int state you want. very much a "make it faster/slower please" request 🔥

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🌈 Description 🌈

so here's the tea: power domains hand you callbacks that get executed during system suspend, hibernation, system resume, and during runtime PM transitions — and they run instead of the subsystem-level and driver-level callbacks. not alongside. instead. that's the whole point, and it's honestly kind of a serve 💅

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👑 SEE ALSO 👑

go look at these if you want the full lore:

• the kernel file ./include/linux/pm.h
• struct dev_pm_ops(9)

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⚠️ friendly reminder bestie: keep every name, path and signature exactly as written — no renaming, no "improving", no vibes-based refactoring. the kernel does not accept your creative choices 🙈

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and that's the page! 💜 source-wise it lives under ./include/linux, dated October 2026, and it's the struct dev_pm_domain(9) page. mwah, go forth and manage those power domains 🧚‍♀️⭐🍓