v4l2_disable_ioctl(9)

💅 v4l2_disable_ioctl(9)

Kernel API Manual — ok bestie, grab a snack, this one's short but it's giving "small but mighty" ✨

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🌸 NAME 🌸

v4l2_disable_ioctl — mark that a given command isn't implemented. shouldn't use core locking 🫶

Like, you're literally putting a little "nope, not this one" sticker on an ioctl. That's the whole vibe. Also: shouldn't use core locking. Noted. Periodt.

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🎀 SYNOPSIS 🎀

void v4l2_disable_ioctl (struct video_device *vdev , unsigned int cmd );

That's it. Two args. No drama. 💅

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🦋 ARGUMENTS 🦋

• vdev — pointer to struct video_device. This is the video device we're talking about, the main character in this story 👑
• cmd — ioctl command. The specific command you're flagging as "not a thing here" 🙈

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✨ DESCRIPTION ✨

Okay so picture this: you're writing a driver and you have exactly one v4l2_ioctl_ops struct. One! And you don't wanna write a whole separate ops struct for every single card variant, because that's exhausting and honestly a lot 😭

That's where this function comes in. It lets drivers provide just one v4l2_ioctl_ops struct, but disable ioctls based on the specific card that is actually found. So like — this card doesn't do that ioctl? Boom, disabled. Elegant. Iconic. Lowkey genius.

### 💀 NOTE 💀 This must be called before video_register_device. Like, before. If you do it after, you're doing it wrong and the vibe check will fail, bestie. Do not skip this, fr fr. See also the comments for determine_valid_ioctls. Go read them. They're in there for a reason 🫶

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🌈 SEE ALSO 🌈

Kernel file ./include/media/v4l2-dev.h — and honestly? The whole extended family is showing up for this one. Buckle in:

enum vfl_devnode_type(9), enum vfl_devnode_direction(9), enum v4l2_video_device_flags(9), struct v4l2_prio_state(9), v4l2_prio_init(9), v4l2_prio_change(9), v4l2_prio_open(9), v4l2_prio_close(9), v4l2_prio_max(9), v4l2_prio_check(9), struct v4l2_file_operations(9), struct video_device(9), media_entity_to_video_device(9), to_video_device(9), __video_register_device(9), video_register_device(9), video_register_device_no_warn(9), video_unregister_device(9), video_device_alloc(9), video_device_release(9), video_device_release_empty(9), video_get_drvdata(9), video_set_drvdata(9), video_devdata(9), video_drvdata(9), video_device_node_name(9), video_is_registered(9), v4l2_debugfs_root(9), video_device_pipeline_start(9), __video_device_pipeline_start(9), video_device_pipeline_stop(9), __video_device_pipeline_stop(9), video_device_pipeline_alloc_start(9), video_device_pipeline(9)

Yeah. That's thirty-plus entries. Whole friend group pulled up 💖

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🧚 Cute little sign-off: this page lives under ./include/media and it's dated October 2026. Slay, go disable some ioctls responsibly ✨🦋🍓