READ_LINE_YUV_SEMIPLANAR(9)

💅 READ_LINE_YUV_SEMIPLANAR 💅

okay so first things first, bestie: this is from the kernel API manual, section 9 (iykyk), and it's genuinely one of those "macro that writes code for you" situations that sounds scary but is actually kind of iconic once it clicks ✨

It's a generic generator for a read_line function — like, it builds the function for you 🫶 — and it's the one you reach for when you're dealing with yuv formats with two planes where block_w == block_h == 1. No cap, that's the whole vibe check for when this applies.

✨ SYNOPSIS ✨

READ_LINE_YUV_SEMIPLANAR (function_name , pixel_1_name , pixel_2_name ,
pixel_1_type , pixel_2_type , callback , ... );

literally just pass the args and let the preprocessor do her main character thing 💅

🎀 ARGUMENTS 🎀

• function_name — the name of the function you want generated. yeah. it names itself. slay.
• pixel_1_name — a temporary pixel name for the first plane, used inside the __VA_ARGS__ parameters 🦋
• pixel_2_name — same deal but for the second plane, also used in the __VA_ARGS__ parameters 🌸
• pixel_1_type — here's where you say what type you want the pixel pointer cast to on plane 1 ✨
• pixel_2_type — and what type to cast the pixel pointer to on plane 2 💜
• callback — the callback that gets called for each pixels. this function should take (struct conversion_matrix*, __VA_ARGS__) as parameter and return a pixel_argb_u16 🔥
• ... — variable arguments. these are the arguments to pass inside the callback — and you can use pixel_1_name and pixel_2_name to access the current pixel values 👑

the callback contract is lowkey the whole point: (struct conversion_matrix*, __VA_ARGS__) in, pixel_argb_u16 out. don't fumble it 🙈

🌈 SEE ALSO 🌈

Kernel file ./drivers/gpu/drm/vkms/vkms_formats.c — that's the home base, go look at her 💖

And the whole friend group:

• packed_pixels_offset(9)
• packed_pixels_addr(9)
• get_block_step_bytes(9)
• packed_pixels_addr_1x1(9)
• get_subsampling(9)
• get_subsampling_offset(9)
• READ_LINE(9)
• READ_LINE_ARGB8888(9)
• READ_LINE_le16161616(9)
• vkms_writeback_row(9)
• get_pixel_read_line_function(9)
• swap_uv_columns(9)
• get_conversion_matrix_to_argb_u16(9)
• get_pixel_write_function(9)

that's the page, bestie 🫶 this one lives at ./drivers/gpu/drm/vkms, dated October 2026 — go read the source, it ate 💀✨