devm_regist..._off_handler(9)

💖 devm_regist..._off_handler(9) 💖

okay bestie, welcome to the Kernel API Manual ✨ this one's all about devm_register_sys_off_handler — the resource-managed way to sign your device up for the whole "system is going bye-bye" moment. no cap, it's lowkey iconic.

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✨ NAME ✨

devm_register_sys_off_handler — register a sys-off handler 🎀

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🌸 SYNOPSIS 🌸

int devm_register_sys_off_handler (struct device *dev , enum
sys_off_mode mode , int priority , int (*callback)(struct sys_off_data
*data) , void *cb_data );

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🦋 ARGUMENTS 🦋

• dev — the device that's registering the handler 🫶 like, this is who's claiming it
• mode — sys-off mode 💅
• priority — handler priority, so the important ones go first, obviously
• callback — the callback function ⭐ this is the main character that actually runs
• cb_data — callback argument, the lil bundle of stuff you hand to callback

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💜 DESCRIPTION 💜

Registers a resource-managed sys-off handler. the "resource-managed" part is the whole vibe — it's tied to dev and gets cleaned up for you, iykyk 🔥

Returns zero on success, or an error code on failure. so like, 0 = slay, anything else = check the code, bestie 😭

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🌈 SEE ALSO 🌈

all from the kernel file ./kernel/reboot.c — go read the whole friend group:

• emergency_restart(9)
• register_reboot_notifier(9)
• unregister_reboot_notifier(9)
• register_restart_handler(9)
• unregister_restart_handler(9)
• do_kernel_restart(9)
• kernel_restart(9)
• kernel_halt(9)
• register_sys_off_handler(9)
• unregister_sys_off_handler(9)
• devm_register_power_off_handler(9)
• devm_register_restart_handler(9)
• register_platform_power_off(9)
• unregister_platform_power_off(9)
• do_kernel_power_off(9)
• kernel_can_power_off(9)
• kernel_power_off(9)
• orderly_poweroff(9)
• orderly_reboot(9)
• hw_failure_emergency_action_func(9)
• hw_failure_emergency_schedule(9)
• __hw_protection_trigger(9)

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okay that's the whole page, mwah 💋 this one lives in ./kernel, dated October 2026 — same manual name, same date, no notes. periodt. 👑