acpi_subsys_resume(9)

📦 version 7.3.1, in nixpkgs unstable

💖 acpi_subsys_resume — the kernel-API manual, bestie edition 💖

okay so this is a page from the Kernel API Manual (manual name: acpi_subsys_resume, section 9 — the fancy kernel-internals section, iykyk), and it's about one tiny little function that wakes your device back up. it's short, it's sweet, it's giving "little function, big responsibility." let's get into it ✨

🌸 NAME 🌸

acpi_subsys_resume — literally just: Resume device using ACPI. that's it. that's the whole vibe. your device is asleep, ACPI is the friend who goes "girl, wake UP" 🫶

✨ SYNOPSIS ✨

int acpi_subsys_resume (struct device *dev );

so it returns an int (because of course it does, every kernel function does), it's called acpi_subsys_resume, and it takes exactly one thing: a pointer to a struct device. no cap, that's the whole signature 💅

🎀 ARGUMENTS 🎀

  • dev — the Device to Resume. that's the one, that's the little guy you're bringing back to life. main character energy, honestly 👑

🦋 DESCRIPTION 🦋

okay so here's what's actually happening, and it's lowkey elegant:

it uses ACPI to put the given device into the full-power state — but only if that device hasn't already been powered up during the early resume phase. like, if someone already woke it up earlier in the process, no need to double-dip, we're not doing redundant work in this house 🙈

and then, on top of that, it carries out the generic resume procedure for the device — this is during the system's transition into the working state, so basically when everything's coming back online and we're all returning to our normal lives 💫

so: full power (conditionally!) + generic resume = device is back, awake, and thriving. periodt 🌈

nothing scary here, no undefined behaviour, no warnings, we're just being polite to hardware. still — conditional logic means "if it's already powered, skip that step," so don't go assuming it always flips the power state 💖

🔥 SEE ALSO 🔥

buckle up bestie, this is the long one, but every single one of these is a real sibling function and they all deserve their moment 💅

the kernel file this lives in is ./drivers/acpi/device_pm.c and here's the whole friend group:

like, the whole suspend/resume/freeze/poweroff cinematic universe is right there. go read them, they're all icons 🧚

🍓 the cute sign-off 🍓

this page lives in ./drivers/acpi, and it's dated October 2026 — so yeah, it's from the future, and it's still serving 💜 mwah, go wake up some hardware, bestie 🌸💖✨

📦 where this page comes from