STRUCT MEDIA_DEVICE_OPS(9)

🎀 NAME 🎀

okay so bestie, this is struct media_device_ops — the media device operations struct 💅 like, it's the lil bundle of function pointers that tells a media device how to behave. from the struct media_device_ops(9) page in the Kernel API Manual, and yes we're getting into it ✨

🌸 SYNOPSIS 🌸

struct media_device_ops {
    int (*link_notify)(struct media_link *link, u32 flags, unsigned int
notification);
    struct media_request *(*req_alloc)(struct media_device *mdev);
    void (*req_free)(struct media_request *req);
    int (*req_validate)(struct media_request *req);
    void (*req_queue)(struct media_request *req);
 };

lowkey iconic struct ngl 🫶

✨ Members ✨

• link_notify — the link state change notification callback 🦋 bestie this one gets called with the graph_mutex held, so like… be aware ok?
• req_alloc — allocates a request. set this if you need to allocate a struct larger then struct media_request 👑 and heads up: req_alloc and req_free must either both be set or both be NULL — no mix-and-match, it's giving all or nothing 💀
• req_free — frees a request. set this if req_alloc was set as well, otherwise leave it to NULL 🎀 they're a matching set fr fr
• req_validate — validates a request, but does not queue it yet 🙈 the req_queue_mutex lock is held when this op is called, so yeah, mind that 🔥
• req_queue — queues up a validated request, and it cannot fail 💅 if something goes wrong while queueing this request, then it should be marked as such internally in the driver, and any related buffers must eventually return to vb2 with state VB2_BUF_STATE_ERROR 😭

the req_queue_mutex lock is held when this op is called too. and listen — it is important that vb2 buffer objects are queued last, after all other object types are queued 👑 because queueing a buffer kickstarts the request processing, so like, all other objects related to the request (and thus the buffer) must be available to the driver. and once a buffer is queued, then the driver can complete or delete objects from the request before req_queue exits 🌟 main character timing honestly

🦋 SEE ALSO 🦋

kernel file ./include/media/media-device.h — plus these besties 💖

• struct media_entity_notify(9)
• struct media_device(9)
• media_device_init(9)
• media_device_cleanup(9)
• __media_device_register(9)
• media_device_register(9)
• media_device_unregister(9)
• media_device_register_entity(9)
• media_device_unregister_entity(9)
• media_device_register_entity_notify(9)
• media_device_unregister_entity_notify(9)
• media_device_pci_init(9)
• __media_device_usb_init(9)
• media_device_usb_init(9)
• media_set_bus_info(9)

and that's the whole vibe check 🧚 this one lives in ./include/media, dated October 2026, straight from the Kernel API Manual — go read the source, slay, periodt 💜🌸