v4l2_detect_gtf(9)

okay so bestie, this is v4l2_detect_gtf(9) from the Kernel API Manual, and it’s giving “can I tell if these timings are GTF?” energy 🌸 no cap, we are keeping every single argument and detail, periodt.

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NAME ✨

v4l2_detect_gtf — detect if the given timings follow the GTF standard 💅

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SYNOPSIS 🎀

bestie, here’s the whole signature, exactly as it is:

bool v4l2_detect_gtf (unsigned int frame_height , unsigned int hfreq ,
       unsigned int vsync , u32 polarities , bool interlaced , struct
       v4l2_fract aspect , const struct v4l2_dv_timings_cap *cap , struct
       v4l2_dv_timings *fmt );

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ARGUMENTS 💖

okay, argument-by-argument, let’s go:

• frame_height — the total height of the frame (including blanking) in lines. literally the whole vertical situation, blanking included 👑
• hfreq — the horizontal frequency in Hz. hz-coded, iykyk ⚡
• vsync — the height of the vertical sync in lines 🦋
• polarities — the horizontal and vertical polarities (same as struct v4l2_bt_timings polarities) — yes, that exact struct vibe ✨
• interlaced — if this flag is true, it indicates interlaced format 🌀
• aspect — preferred aspect ratio. GTF has no method of determining the aspect ratio in order to derive the image width from the image height, so it has to be passed explicitly. Usually the native screen aspect ratio is used for this. If it is not filled in correctly, then 16:9 will be assumed 🌈
• cap — the v4l2_dv_timings_cap capabilities 💀
• fmt — the resulting timings 🎯

bestie heads-up: GTF is not out here guessing image width from image height, so aspect has to be given explicitly. If it’s not filled in correctly, 16:9 is assumed 🙈

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DESCRIPTION 🦋

This function will attempt to detect if the given values correspond to a valid GTF format. If so, then it will return true, and fmt will be filled in with the found GTF timings. no cap — that’s the whole plot, and it ate 💅

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SEE ALSO 🌟

Kernel file: ./include/media/v4l2-dv-timings.h — that’s the source file, bestie 🫶

and the whole reference squad, in order:

• v4l2_calc_timeperframe(9)
• v4l2_check_dv_timings_fnc(9)
• v4l2_valid_dv_timings(9)
• v4l2_enum_dv_timings_cap(9)
• v4l2_find_dv_timings_cap(9)
• v4l2_find_dv_timings_cea861_vic(9)
• v4l2_match_dv_timings(9)
• v4l2_print_dv_timings(9)
• v4l2_detect_cvt(9)
• v4l2_calc_aspect_ratio(9)
• v4l2_dv_timings_aspect_ratio(9)
• can_reduce_fps(9)
• struct v4l2_hdmi_colorimetry(9)

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mwah 💋 — the footer’s source is ./include/media, the date is October 2026, and the page is v4l2_detect_gtf(9). bye bestie, go detect those timings 🫶