STRUCT MALI_C55_AE_5BIN_HIST(9)

✨ struct mali_c55_ae_5bin_hist ✨

okay bestie so this is from the Kernel API Manual (section 9, kernel API pages, iykyk) and it's literally just a struct but she's an icon 💅

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🎀 NAME 🎀

struct mali_c55_ae_5bin_hist — Auto Exposure 5-bin histogram statistics. that's the whole vibe. it holds stats. about histograms. with five bins. and auto exposure. slay 💖

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🦋 SYNOPSIS 🦋

struct mali_c55_ae_5bin_hist {
    __u16 hist0;
    __u16 hist1;
    __u16 hist3;
    __u16 hist4;
 };

not me pointing out that there is no hist2 in here 😭 that's not a typo, that's the whole plot twist, keep reading bestie 🫶

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🌸 Members 🌸

• hist0 — 16-bit normalised pixel count for the 0th intensity bin. she's number zero and she's thriving ✨
• hist1 — 16-bit normalised pixel count for the 1st intensity bin. cutie. does her job 💜
• hist3 — 16-bit normalised pixel count for the 3rd intensity bin. yes we skipped 2. no we will not be taking questions. it's giving mysterious 👑
• hist4 — 16-bit normalised pixel count for the 4th intensity bin. the last one, the final girl, the main character energy 🌈

fr fr there's no member for the centre bin. that's not an accident, that's ✨by design✨

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💖 Description 💖

so the ISP generates a 5-bin histogram of normalised pixel counts within bins of pixel intensity, for each of 225 possible zones within a frame. 225 zones!! that's so many zones, she's been booked and busy 💀

here's the gag tho: the centre bin of the histogram for each zone is not available from the hardware. nope. the hardware said "not my problem" 🙈

so you, yes you, have to calculate it yourself by subtracting the values of hist0, hist1, hist3 and hist4 from 0xffff, exactly like this equation:

hist2 = 0xffff - (hist0 + hist1 + hist3 + hist4)

write that down, put it on a sticky note, tape it to your monitor 🎀 that's the whole reason hist2 isn't in the struct — you build it yourself, you're the CEO of bin 2, periodt 🔥

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👑 SEE ALSO 👑

the Kernel file ./include/uapi/linux/media/arm/mali-c55-config.h and honestly a whole friend group of structs and enums, all linked below, all iconic:

• struct mali_c55_ae_1024bin_hist(9)
• struct mali_c55_awb_average_ratios(9)
• struct mali_c55_af_statistics(9)
• struct mali_c55_stats_buffer(9)
• enum mali_c55_param_block_type(9)
• struct mali_c55_params_sensor_off_preshading(9)
• enum mali_c55_aexp_hist_tap_points(9)
• enum mali_c55_aexp_skip_x(9)
• enum mali_c55_aexp_skip_y(9)
• enum mali_c55_aexp_row_column_offset(9)
• enum mali_c55_aexp_hist_plane_mode(9)
• struct mali_c55_params_aexp_hist(9)
• struct mali_c55_params_aexp_weights(9)
• struct mali_c55_params_digital_gain(9)
• enum mali_c55_awb_stats_mode(9)
• struct mali_c55_params_awb_gains(9)
• enum mali_c55_params_awb_tap_points(9)
• struct mali_c55_params_awb_config(9)
• struct mali_c55_params_mesh_shading_config(9)
• struct mali_c55_params_mesh_shading_selection(9)
• struct mali_c55_params_ccm(9)
• struct mali_c55_params_gamma(9)
• MALI_C55_PARAMS_MAX_SIZE(9)

like. every single one. we stan a complete cross-reference list 💅

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and that's the page!! source lives at ./include/uapi/linux/media/arm, this edition dropped October 2026, and the whole thing is filed under struct mali_...ae_5bin_hist(9) in section 9 🧚 stan a histogram struct that knows exactly what she is 💖✨🦋