__media_device_register(9)

📦 version 7.3.1, in nixpkgs unstable

✨ __media_device_register(9) ✨

okay so this is a page from the Kernel API Manual, bestie — we're doing __media_device_register(9) today and honestly? it's giving "tiny function, big responsibilities" 💅

🌸 NAME 🌸

__media_device_register — registers a media device element. that's it, that's the vibe 🎀

⭐ SYNOPSIS ⭐

int __media_device_register (struct media_device *mdev , struct module
*owner );

💖 ARGUMENTS 💖

  • mdev — pointer to struct media_device. your main character struct, fr fr 🫶
  • owner — should be filled with THIS_MODULE. like, literally just put that there, iykyk

🦋 DESCRIPTION 🦋

okay so first thing first: users, should, instead, call the media_device_register macro. 👑 not this one directly. this one's the backstage version, the macro is the one with main character energy.

the caller is responsible for initializing the media_device structure before registration. no cap — that's on you. the following fields of media_device must be set:

  • media_device.model — must be filled with the device model name as a NUL-terminated UTF-8 string. and listen: the device/model revision must not be stored in this field. do not do it. 🙈

the following fields are optional (but slay if you fill them in ✨):

  • media_device.serial — a unique serial number stored as a NUL-terminated ASCII string. the field is big enough to store a GUID in text form. if the hardware doesn't provide a unique serial number, this field must be left empty. periodt.
  • media_device.bus_info — represents the location of the device in the system as a NUL-terminated ASCII string. for PCI/PCIe devices, media_device.bus_info must be set to "PCI:" (or "PCIe:") followed by the value of pci_name. for USB devices, the usb_make_path function must be used. this field is used by applications to distinguish between otherwise identical devices that don't provide a serial number. literally the "which one is which" field 💀
  • media_device.hw_revision — the hardware device revision in a driver-specific format. when possible, the revision should be formatted with the KERNEL_VERSION macro. 🎀

💀 NOTE 💀

1. upon successful registration, a character device named media[0-9]+ is created. the device major and minor numbers are dynamic. the model name is exported as a sysfs attribute. cute, right? 🌈 2. unregistering a media device that hasn't been registered is NOT safe. like, NOT NOT. do not test this. this is not a drill, bestie 😭🔥

🎀 RETURN 🎀

returns zero on success or a negative error code. simple as that 🫶

🌟 SEE ALSO 🌟

and that's the whole thing, bestie — go register some media devices responsibly 🧚💜

sign-off tea ☕: this one lives in ./include/media and the version stamp on it is October 2026. iconic behavior tbh 🌸
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