input_register_device(9)

📦 version 7.3.1, in nixpkgs unstable

💖 input_register_device — register device with input core 💖

okay so real talk, bestie, this one is from the Kernel API Manual, section 9, and it's literally the moment your input device becomes official. no cap. 🎀

✨ SYNOPSIS ✨

int input_register_device (struct input_dev *dev );

🌸 ARGUMENTS 🌸

  • dev — the device you're registering. yes queen, that's the whole argument. 🦋

💅 DESCRIPTION 💅

okay so here's the tea. input_register_device registers your device with the input core — like, it's giving "officially introducing your device to the whole friend group" energy. 👑

bestie, before you can do that, the device must be allocated with input_allocate_device and all its capabilities set up before registering. like, don't show up to the party with no capabilities. that's not the vibe. 🙈

and listen — if the function fails, the device must be freed with input_free_device. periodt. don't leave it hanging in memory. 😭

once the device has been successfully registered, though? you can unregister it with input_unregister_device. and in that case, input_free_device should not be called. nope. nope nope nope. the vibes would be off. 🚫

⚠️ ok so this is the part where you need to pay attention, bestie — getting this free/unregister pairing wrong is giving 💀 energy. read it twice. iykyk.

🧚 the managed device situation 🧚

not me about to explain devres... ok so, highkey relevant: this function is also used to register managed input devices (the ones allocated with devm_input_allocate_device). 🌈

those managed input devices need not be explicitly unregistered or freed — their tear down is controlled by the devres infrastructure. it handles it. let it cook. ✨

also worth noting (and this is the iconic part): tear down of managed input devices is internally a 2-step process:

  1. the registered managed input device is first unregistered, but stays in memory and can still handle input_event calls — although events will not be delivered anywhere. 🫥
  2. the freeing of the managed input device happens later, when the devres stack is unwound to the point where device allocation was made. ⭐

like, it's alive but it's not delivering, you know? main character in the memory, ghost in the event delivery. 💀✨

🔥 SEE ALSO 🔥

mwah 💋 this page lives in ./drivers/input, dated October 2026, and it's input_register_device(9) — go register something iconic, bestie. 🎀💜

📦 where this page comes from