v4l2_subdev...date_default(9)

💅 v4l2_subdev_link_validate_default 💅

okay so this page (v4l2_subdev...date_default(9)) is from the Kernel API Manual, and it’s lowkey a little baddie of a function. bestie, we’re validating a media link. no cap. 🦋

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🌸 NAME 🌸

v4l2_subdev_link_validate_default — validates a media link ✨

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✨ SYNOPSIS ✨

bestie, the signature is literally right here:

int v4l2_subdev_link_validate_default (struct v4l2_subdev *sd , struct
media_link *link , struct v4l2_subdev_format *source_fmt , struct
v4l2_subdev_format *sink_fmt );

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🎀 ARGUMENTS 🎀

• sd — pointer to struct v4l2_subdev 🫶
• link — pointer to struct media_link 🔗
• source_fmt — pointer to struct v4l2_subdev_format 💖
• sink_fmt — pointer to struct v4l2_subdev_format 🌸

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🦋 DESCRIPTION 🦋

okay so here’s the tea: this function ensures that width, height, and the media bus pixel code are equal on both source and sink of the link. that’s it, that’s the whole vibe check. it’s giving “link validation main character energy,” and honestly? slay. 💅 periodt.

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💜 SEE ALSO 💜

not me listing the whole kernel friend group 😭 the kernel file ./include/media/v4l2-subdev.h is the mothership, and then there’s literally all of these:

• 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(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_enable_streams(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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xoxo, your kernel bestie 🫶 — source/version: ./include/media / v4l2_subdev...date_default(9), dated October 2026. 💖