v4l2_subdev_enable_streams(9)

💅 v4l2_subdev_enable_streams(9) — the Kernel API Manual glow-up 🎀

okay so bestie, welcome to the v4l2_subdev_enable_streams(9) page from the Kernel API Manual ✨ this is the one that turns streams ON, and we're gonna walk through it together, no cap 🫶

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🌸 NAME 🌸

v4l2_subdev_enable_streams — Enable streams on a pad 💫

like literally, that's the whole job. enabling streams. on a pad. iconic behavior honestly 👑

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🦋 SYNOPSIS 🦋

int v4l2_subdev_enable_streams (struct v4l2_subdev *sd , u32 pad , u64
streams_mask );

three args, one int back, that's the vibe 😌

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✨ ARGUMENTS ✨

• sd — the subdevice 🧚 like, the actual thing you're poking at
• pad — the pad 🌸 your chosen hangout spot on that subdevice
• streams_mask — bitmask of streams to enable 🎀 a whole little bitfield of besties, each bit invited to the party

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💜 DESCRIPTION 💜

okay so here's the tea ☕ this function enables streams on a source pad of a subdevice. the pad is identified by its index, while the streams are identified by the streams_mask bitmask. and the way this slaps? it lets you enable multiple streams on a pad at once 🔥 batch mode, main character energy, we love efficiency 💅

but listen — enabling a stream that's already enabled isn't allowed 🙈 not permitted, not happening, we don't do that here. if streams_mask contains an already enabled stream, this function returns -EALREADY without performing any operation. so it just... stops. full bail. zero side effects, at least 🫶

now for the compatibility lore 🧚 per-stream enable is only available for subdevs that implement the .enable_streams and .disable_streams operations. for other subdevs, this function implements a best-effort compatibility by calling the .s_stream operation — limited to subdevs that have a single source pad. best-effort, bestie. that's the key phrase. don't expect miracles 💀

and hey — drivers that are not stream-aware shall set streams_mask to BIT_ULL(0). literally just that. one bit. that's your whole mask. don't overthink it 🍓

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🌈 RETURN 🌈

• 0 — Success ✨ slay, we did it, no errors, go girl
• -EALREADY — one of the streams in streams_mask is already enabled 😭 bestie it's already on, we can't turn it on again
• -EINVAL — the pad index is invalid, or doesn't correspond to a source pad 💀 wrong pad, wrong vibe, try again
• -EOPNOTSUPP — falling back to the legacy .s_stream operation is impossible because the subdev has multiple source pads 🙈 multi-pad subdev + no stream ops = no path forward, sorry queen

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👑 SEE ALSO 👑

Kernel file ./include/media/v4l2-subdev.h — and honestly the whole extended friend group, they all said hi 💖

• struct v4l2_decode_vbi_line(9)
• enum v4l2_subdev_io_pin_bits(9)
• struct v4l2_subdev_io_pin_config(9)
• struct v4l2_subdev_core_ops(9)
• struct v4l2_subdev_tuner_ops(9)
• struct v4l2_subdev_audio_ops(9)
• struct v4l2_mbus_frame_desc_entry_csi2(9)
• enum v4l2_mbus_frame_desc_flags(9)
• struct v4l2_mbus_frame_desc_entry(9)
• enum v4l2_mbus_frame_desc_type(9)
• struct v4l2_mbus_frame_desc(9)
• enum v4l2_subdev_pre_streamon_flags(9)
• struct v4l2_subdev_video_ops(9)
• struct v4l2_subdev_vbi_ops(9)
• struct v4l2_subdev_sensor_ops(9)
• enum v4l2_subdev_ir_mode(9)
• struct v4l2_subdev_ir_parameters(9)
• struct v4l2_subdev_ir_ops(9)
• struct v4l2_subdev_pad_config(9)
• struct v4l2_subdev_stream_configs(9)
• struct v4l2_subdev_krouting(9)
• struct v4l2_subdev_state(9)
• struct v4l2_subdev_pad_ops(9)
• struct v4l2_subdev_ops(9)
• struct v4l2_subdev_internal_ops(9)
• struct v4l2_subdev_platform_data(9)
• struct v4l2_subdev(9)
• media_entity_to_v4l2_subdev(9)
• vdev_to_v4l2_subdev(9)
• struct v4l2_subdev_fh(9)
• to_v4l2_subdev_fh(9)
• v4l2_set_subdevdata(9)
• v4l2_get_subdevdata(9)
• v4l2_set_subdev_hostdata(9)
• v4l2_get_subdev_hostdata(9)
• v4l2_subdev_get_fwnode_pad_1_to_1(9)
• v4l2_subdev_link_validate_default(9)
• v4l2_subdev_link_validate(9)
• v4l2_subdev_has_pad_interdep(9)
• __v4l2_subdev_state_alloc(9)
• __v4l2_subdev_state_free(9)
• v4l2_subdev_init_finalize(9)
• v4l2_subdev_cleanup(9)
• v4l2_subdev_state_get_format(9)
• v4l2_subdev_state_get_crop(9)
• v4l2_subdev_state_get_compose(9)
• v4l2_subdev_state_get_interval(9)
• v4l2_subdev_get_fmt(9)
• v4l2_subdev_get_frame_interval(9)
• v4l2_subdev_set_routing(9)
• for_each_active_route(9)
• v4l2_subdev_set_routing_with_fmt(9)
• v4l2_subdev_routing_find_opposite_end(9)
• v4l2_subdev_state_get_opposite_stream_format(9)
• v4l2_subdev_state_xlate_streams(9)
• enum v4l2_subdev_routing_restriction(9)
• v4l2_subdev_routing_validate(9)
• v4l2_subdev_disable_streams(9)
• v4l2_subdev_s_stream_helper(9)
• __v4l2_subdev_get_frame_desc_passthrough(9)
• v4l2_subdev_get_frame_desc_passthrough(9)
• v4l2_subdev_lock_state(9)
• v4l2_subdev_unlock_state(9)
• v4l2_subdev_lock_states(9)
• v4l2_subdev_unlock_states(9)
• v4l2_subdev_get_unlocked_active_state(9)
• v4l2_subdev_get_locked_active_state(9)
• v4l2_subdev_lock_and_get_active_state(9)
• v4l2_subdev_init(9)
• v4l2_subdev_call(9)
• v4l2_subdev_call_state_active(9)
• v4l2_subdev_call_state_try(9)
• v4l2_subdev_has_op(9)
• v4l2_subdev_notify_event(9)
• v4l2_subdev_is_streaming(9)

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aaaand that's the whole page bestie!! 🎀 this lil masterpiece lives in ./include/media, dated October 2026, and it's filed under the name v4l2_subdev_enable_streams(9) — go forth and enable those streams, you're gonna eat 💅✨🦋