powercap_reg...control_type(9)

💅 powercap_reg...control_type(9) — the Kernel API Manual, bestie edition

okay so bestie, you're looking at a page from the Linux Kernel API Manual. It lives in ./include/linux. Yes it does. Let's get into it ✨

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🌸 NAME 🌸

powercap_register_control_type — the function that registers a control_type with the framework. That's literally the whole job. She registers. She slays. Periodt. 💅

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🎀 SYNOPSIS 🎀

struct powercap_control_type * powercap_register_control_type (struct
powercap_control_type *control_type , const char *name , const struct
powercap_control_type_ops *ops );

that's the signature, bestie — <purple>struct powercap_control_type *</purple> comes back out, and you hand her three things on the way in. 🦋

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✨ ARGUMENTS ✨

• control_type — Pointer to memory you (the client) allocated for the control type structure storage. 🫶 But here's the plot twist: if this is NULL, the powercap framework will allocate the memory and own it. The absolute glow-up reason you'd pass it in yourself is that your client can embed this data inside its own data structures and allocate it all in a single call, which prevents multiple allocations. efficiency icon behavior, ngl. 👑
• name — The name of this control_type. It's what gets shown in the sysfs interface, so pick something cute — or at least something legible. 🌈
• ops — Callbacks for the control type. This parameter is optional, so like... no pressure. 🙈

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💖 DESCRIPTION 💖

So what does she actually do? She's used to create a control_type with the power capping class. A control_type can represent a type of technology, and that technology can control a whole range of power zones. 💀

For example, a control_type can be RAPL — that's Running Average Power Limit — for Intel® 64 and IA-32 Processor Architectures. iconic.

The name can be any string, but it must be unique — no cap, if it's not unique, this function returns NULL. 😭

On success, you get a pointer to the control_type instance back. slay. ✨

⚠️ lowkey important: the ops argument is optional, but the unique-name thing is not. Duplicate name = NULL = sad times. 🥲

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🦋 SEE ALSO 🦋

• Kernel file ./include/linux/powercap.h
• struct powercap_control_type_ops(9)
• struct powercap_control_type(9)
• struct powercap_zone_ops(9)
• struct powercap_zone(9)
• struct powercap_zone_constraint_ops(9)
• struct powercap_zone_constraint(9)
• powercap_set_zone_data(9)
• powercap_get_zone_data(9)
• powercap_unregister_control_type(9)
• powercap_register_zone(9)
• powercap_unregister_zone(9)

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and that's the page, bestie 🧚💜 she ships from ./include/linux, the version is stamped October 2026, and she goes by the handle powercap_reg...control_type(9). go forth and register your control types responsibly ✨🎀🍓