scmi_userspace_notifier(9)

✨ scmi_userspace_notifier(9) ✨

okay so bestie, this one's from the Kernel API Manual and it's lowkey one of those tiny callback functions that has main character energy — like it's small but the way it just... decides the fate of your whole system? iconic. 🎀

It's called scmi_userspace_notifier, and it's the notifier callback that acts on SystemPower Notifications. yes. that kind of power. 💅

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🌸 SYNOPSIS 🌸

int scmi_userspace_notifier (struct notifier_block *nb , unsigned long
event , void *data );

like, that's the whole signature. short. sweet. devastating. 🦋

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💖 ARGUMENTS 💖

• nb — reference to the related notifier block. it's giving "your VIP pass to the notifier chain" energy 🎟️
• event — the SystemPower notification event id. literally the label on the notification telling you what kind of moment this is ✨
• data — the SystemPower event report. the actual tea. the payload. the whole reason we're here 🫖

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🔥 DESCRIPTION 🔥

so this callback is in charge of decoding the received SystemPower report and then acting accordingly — triggering either a graceful or a forceful system transition. ngl that's a lot of responsibility for one little function but she ate, fr fr 👑

⚠️ okay important caveat bestie, listen up: once a valid SCMI SystemPower event starts being served, any other following SystemPower notification received from the same SCMI instance (handle) will be ignored. periodt. no second chances. 💀

so like, first valid event wins, everything after that from the same handle is just background noise. iykyk 🙈

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⭐ RETURN ⭐

NOTIFY_OK — returned once a valid SystemPower event has been successfully processed. that's the happy ending, we love to see it 🥹💜

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🌈 SEE ALSO 🌈

• Kernel file ./drivers/firmware/arm_scmi/scmi_power_control.c
• struct scmi_syspower_conf(9)
• scmi_reboot_notifier(9)
• scmi_request_forceful_transition(9)
• scmi_request_graceful_transition(9)

go read those if you want the full lore, they're all in the same friend group 🫶

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and that's the page!! sourced from ./drivers/firmware/arm_scmi, dated October 2026, and yes she's still out here in the Kernel API Manual being iconic. mwah 💋✨🧚