ENUM VB2_MEMORY(9)

💅 enum vb2_memory(9) — like, the actual kernel API manual, bestie

okay so this is a page from the Kernel API Manual and it's all about enum vb2_memory — literally just the vibe-check of which memory model is being used to make buffers visible on userspace. that's it. that's the whole thing. but it's important so pay attention 🎀

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✨ NAME ✨

enum vb2_memory — the type of memory model used to make the buffers visible on userspace. no cap, that's the job. 🦋

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🌸 SYNOPSIS 🌸

here's the whole enum, bestie, exactly as it lives in the source:

enum vb2_memory {
    VB2_MEMORY_UNKNOWN ,
    VB2_MEMORY_MMAP ,
    VB2_MEMORY_USERPTR ,
    VB2_MEMORY_DMABUF

};

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👑 Constants 👑

okay so these are the four options. four. that's it. slay 💅

• VB2_MEMORY_UNKNOWN — buffer status is unknown, or it's just not being used yet on userspace. it's giving "no thoughts, head empty" 🫧
• VB2_MEMORY_MMAP — the buffers are allocated by the Kernel, and they're memory mapped via mmap ioctl. and listen — this model is also the one in play when the user is using the buffers via read or write system calls. so it's a two-for-one situation, iconic ✨
• VB2_MEMORY_USERPTR — the buffers were allocated in userspace, and it's memory mapped via mmap ioctl. (yes, that's what it says. userspace allocation, mmap ioctl mapping. periodt 💖)
• VB2_MEMORY_DMABUF — the buffers are passed to userspace via DMA buffer. that's the whole description. short and mysterious, main character energy 🔥

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💜 SEE ALSO 💜

okay this list is long and I respect it immensely. here's every single one, no skipping, we don't do that here 🎀

Kernel file ./include/media/videobuf2-core.h:

• struct vb2_mem_ops(9)
• struct vb2_plane(9)
• enum vb2_io_modes(9)
• enum vb2_buffer_state(9)
• struct vb2_buffer(9)
• struct vb2_ops(9)
• struct vb2_buf_ops(9)
• struct vb2_queue(9)
• vb2_queue_allows_cache_hints(9)
• vb2_plane_vaddr(9)
• vb2_plane_cookie(9)
• vb2_buffer_done(9)
• vb2_discard_done(9)
• vb2_wait_for_all_buffers(9)
• vb2_core_querybuf(9)
• vb2_core_reqbufs(9)
• vb2_core_create_bufs(9)
• vb2_core_prepare_buf(9)
• vb2_core_remove_bufs(9)
• vb2_core_qbuf(9)
• vb2_core_dqbuf(9)
• vb2_core_streamon(9)
• vb2_core_streamoff(9)
• vb2_core_expbuf(9)
• vb2_core_queue_init(9)
• vb2_core_queue_release(9)
• vb2_queue_error(9)
• vb2_mmap(9)
• vb2_get_unmapped_area(9)
• vb2_core_poll(9)
• vb2_read(9)
• vb2_write(9)
• vb2_thread_fnc(9)
• vb2_thread_start(9)
• vb2_thread_stop(9)
• vb2_is_streaming(9)
• vb2_fileio_is_active(9)
• vb2_get_num_buffers(9)
• vb2_is_busy(9)
• vb2_get_drv_priv(9)
• vb2_set_plane_payload(9)
• vb2_get_plane_payload(9)
• vb2_plane_size(9)
• vb2_start_streaming_called(9)
• vb2_clear_last_buffer_dequeued(9)
• vb2_get_buffer(9)
• vb2_buffer_in_use(9)
• vb2_verify_memory_type(9)
• vb2_request_object_is_buffer(9)
• vb2_request_buffer_cnt(9)

like. fifty-ish cross-references. obsessed with the dedication honestly 🌈

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ngl bestie, that VB2_MEMORY_USERPTR entry reads exactly like the VB2_MEMORY_MMAP one about mmap ioctl — I'm just telling you what the page says, don't come for me 🙈

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and that's the whole page!! mwah 💋 it lives at ./include/media, and the version/date on this lil beauty is October 2026 — so yeah, future vibes only. go forth and buffer correctly, bestie 🧚‍♀️⭐🫶