STRUCT V4L2_CAPABILITY(9)

💖 struct v4l2_capability(9) 💖

okay so bestie, this is a page from the Kernel API Manual — yes, the kernel, the big one — and we're about to get into struct v4l2_capability, which is literally the struct that describes your V4L2 device caps, returned by VIDIOC_QUERYCAP. it's giving "who am I and what can I do" energy for your video device. slay. 🎀

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✨ NAME ✨

struct v4l2_capability — describes the V4L2 device caps that get returned by VIDIOC_QUERYCAP 🦋

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🌸 SYNOPSIS 🌸

okay, deep breath, here's the whole shape of it, exactly as it is:

struct v4l2_capability {
    __u8 driver[16];
    __u8 card[32];
    __u8 bus_info[32];
    __u32 version;
    __u32 capabilities;
    __u32 device_caps;
    __u32 reserved[3];
 };

yes the closing brace is indented by one space in the original and we are respecting it. periodt. 💅

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👑 Members 👑

so these are the fields, and every single one of them matters, okay? no skimming:

• driver — the name of the driver module, like "bttv" for example. this is the driver's little name tag 🏷️
• card — the name of the card, like "Hauppauge WinTV". iconic hardware branding moment 💖
• bus_info — the name of the bus, e.g. "PCI:" + pci_name(pci_dev). it's literally telling you where this thing lives on the bus 🌈
• version — this one holds a KERNEL_VERSION ⭐
• capabilities — the capabilities of the physical device as a whole. the full picture, the whole vibe check of the entire device 🔥
• device_caps — the capabilities accessed via this particular device (node). so like, this specific node's own personal set of powers, not the whole device's 👑
• reserved — reserved fields for future extensions. the kernel is holding seats for future features, we love a forward-thinking icon 🙈

ngl bestie, do not go touching reserved — it's reserved for future extensions, that's literally its whole job. leave it alone. 💀

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🦋 SEE ALSO 🦋

if you're obsessed (and you should be), go look at the kernel file ./include/uapi/linux/videodev2.h, and also these absolute main characters:

• struct v4l2_plane(9)
• struct v4l2_buffer(9)
• v4l2_timeval_to_ns(9)
• struct v4l2_exportbuffer(9)
• struct v4l2_selection(9)
• struct v4l2_plane_pix_format(9)
• struct v4l2_pix_format_mplane(9)
• struct v4l2_sdr_format(9)
• struct v4l2_meta_format(9)
• struct v4l2_format(9)
• struct v4l2_event_motion_det(9)
• struct v4l2_create_buffers(9)
• struct v4l2_remove_buffers(9)

that's the whole friend group, fr fr. go say hi 💜

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okay that's the page!! this one lives in ./include/uapi/linux, dated October 2026, and it's struct v4l2_capability(9) from the Kernel API Manual — mwah, tysm for reading bestie, you ate this whole thing up 💅✨🌸🫶