v4l2_m2m_streamon(9)

💅 v4l2_m2m_streamon(9) — like, the Kernel API Manual, bestie ✨

Okay so first thing first: this page lives in the Kernel API Manual and it's literally called v4l2_m2m_streamon(9). Same name up top, same name at the bottom, iconic symmetry, we love a consistent brand 🎀

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🌸 NAME 🌸

v4l2_m2m_streamon — turn on streaming for a video queue. That's it. That's the whole gig. Lights, camera, stream. 🔥

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✨ SYNOPSIS ✨

int v4l2_m2m_streamon (struct file *file , struct v4l2_m2m_ctx *m2m_ctx
, enum v4l2_buf_type type );

Notice it returns an int, so like… check it, okay? 👀

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🦋 ARGUMENTS 🦋

Three args, no notes, let's get into it:

• file — pointer to struct file. Yes it's a pointer, no you don't get to be normal about it.
• m2m_ctx — the m2m context assigned to the instance, given by struct v4l2_m2m_ctx. It's the whole little world your instance lives in 🫶
• type — the type of the V4L2 buffer, as defined by enum v4l2_buf_type. Which queue are we waking up? You're telling it. Main character decision, honestly. 👑

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💜 SEE ALSO 💜

Bestie, this list is LONG and I'm obsessed, it's giving "my mutuals" energy. All of these are (9) kernel API pages, plus one very important header file:

Kernel file 👇

• ./include/media/v4l2-mem2mem.h

And the structs, the OGs 🏛️:

• struct v4l2_m2m_ops(9)
• struct v4l2_m2m_queue_ctx(9)
• struct v4l2_m2m_ctx(9)
• struct v4l2_m2m_buffer(9)

The scheduler / job-finish girlies ⚙️:

• v4l2_m2m_get_curr_priv(9)
• v4l2_m2m_get_vq(9)
• v4l2_m2m_try_schedule(9)
• v4l2_m2m_job_finish(9)
• v4l2_m2m_buf_done_and_job_finish(9)

State machine besties (they track the vibes) 🔄:

• v4l2_m2m_clear_state(9)
• v4l2_m2m_mark_stopped(9)
• v4l2_m2m_dst_buf_is_last(9)
• v4l2_m2m_has_stopped(9)
• v4l2_m2m_is_last_draining_src_buf(9)
• v4l2_m2m_last_buffer_done(9)
• v4l2_m2m_suspend(9)
• v4l2_m2m_resume(9)

The buffer bargain-bin run (all your ioctl-ish faves) 📼:

• v4l2_m2m_reqbufs(9)
• v4l2_m2m_querybuf(9)
• v4l2_m2m_qbuf(9)
• v4l2_m2m_dqbuf(9)
• v4l2_m2m_prepare_buf(9)
• v4l2_m2m_create_bufs(9)
• v4l2_m2m_expbuf(9)

The ✨ counterpart ✨ (you know exactly who):

• v4l2_m2m_streamoff(9)

Streaming-state updaters, they keep the lore accurate 📖:

• v4l2_m2m_update_start_streaming_state(9)
• v4l2_m2m_update_stop_streaming_state(9)

Codec command crew 🎬:

• v4l2_m2m_encoder_cmd(9)
• v4l2_m2m_decoder_cmd(9)

The I/O girlies (poll + mmap, the classic duo) 🌀:

• v4l2_m2m_poll(9)
• v4l2_m2m_mmap(9)

Lifecycle, literally birth to rebirth 🌱:

• v4l2_m2m_init(9)
• v4l2_m2m_release(9)
• v4l2_m2m_get(9)
• v4l2_m2m_put(9)
• v4l2_m2m_ctx_init(9)
• v4l2_m2m_ctx_release(9)

Queueing + counting 🧮:

• v4l2_m2m_buf_queue(9)
• v4l2_m2m_num_src_bufs_ready(9)
• v4l2_m2m_num_dst_bufs_ready(9)

Peeking at buffers, no cap 👀:

• v4l2_m2m_next_buf(9)
• v4l2_m2m_next_src_buf(9)
• v4l2_m2m_next_dst_buf(9)
• v4l2_m2m_last_buf(9)
• v4l2_m2m_last_src_buf(9)
• v4l2_m2m_last_dst_buf(9)

Loop-de-loop macros, the safe ones included 🎠:

• v4l2_m2m_for_each_dst_buf(9)
• v4l2_m2m_for_each_src_buf(9)
• v4l2_m2m_for_each_dst_buf_safe(9)
• v4l2_m2m_for_each_src_buf_safe(9)

Grab the queue directly 🫳:

• v4l2_m2m_get_src_vq(9)
• v4l2_m2m_get_dst_vq(9)

Removal squad (removing stuff is also a love language) 🗑️:

• v4l2_m2m_buf_remove(9)
• v4l2_m2m_src_buf_remove(9)
• v4l2_m2m_dst_buf_remove(9)
• v4l2_m2m_buf_remove_by_buf(9)
• v4l2_m2m_src_buf_remove_by_buf(9)
• v4l2_m2m_dst_buf_remove_by_buf(9)

And the metadata copy-er, we stan a thorough queen 💫:

• v4l2_m2m_buf_copy_metadata(9)

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Fr fr: that's the entire SEE ALSO list, unedited, nobody got left out of the group chat. 💖

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Okay bye ily, this page was brought to you by the directory ./include/media, dated October 2026, and it's v4l2_m2m_streamon(9) all the way down. Slay, stream responsibly, and go read v4l2_m2m_streamoff(9) when you're done. 🌈👑💅