optc35_get_crc(9)

💅 optc35_get_crc(9) — like, the Kernel API Manual but make it make sense 🎀

okay so bestie, welcome to optc35_get_crc, a lil function from the Kernel API Manual and honestly? she's giving "quietly essential." let's get into it ✨

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✨ NAME ✨

optc35_get_crc — grab the CRC result for each color component, one at a time, no cap 💅

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🌸 SYNOPSIS 🌸

bool optc35_get_crc (struct timing_generator *optc , uint8_t idx ,
uint32_t *r_cr , uint32_t *g_y , uint32_t *b_cb );

like, that's the whole signature. she takes four args and returns a bool. periodt 🫶

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🦋 ARGUMENTS 🦋

• optc — your timing_generator instance. the main character, honestly 👑
• idx — the index of the crc engine you wanna get the CRC from. which one? this one 🔥
• r_cr — the primary CRC signature for red data. red girlie 💋
• g_y — the primary CRC signature for green data. green flag behavior 🌱
• b_cb — the primary CRC signature for blue data. blue era 💙

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💖 DESCRIPTION 💖

so what does she actually do? this function reads the CRC signature straight out of the OPTC registers. and here's the cute part — there are three registers keeping the CRC result per color component (RGB). three registers. one for each vibe. 🌈

now, it's different depending on your DCN version, so pay attention bestie:

• If CRC32 registers (OTG_CRC0_DATA_R32/G32/B32) are available, read from the 32-bit CRC registers. also!! DCN 3.6+ supports both CRC-32 and CRC-16 polynomials, and you select between them via OTG_CRC_POLY_SEL. iconic, honestly ✨
• Otherwise, read from the legacy 16-bit CRC registers (OTG_CRC0_DATA_RG/B) — and lowkey those only support the CRC-16 polynomial. no choices, no options, just vibes 💀

ngl this is the whole "if you have the fancy registers use 'em, otherwise fall back" situation, so don't assume you're always getting 32-bit data, mkay? 🙈

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⭐ RETURN ⭐

• If CRC is disabled → return false 😭 (no data for you)
• Otherwise → return true, and the CRC results land in the parameters. slay 💅

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🎀 SEE ALSO 🎀

• Kernel file ./drivers/gpu/drm/amd/display/dc/optc/dcn35/dcn35_optc.c — go read the source, iykyk 📖
• optc35_set_odm_combine(9) — her sibling, also worth a look 👀

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and that's the page!! mwah 💋 this was optc35_get_crc(9) from the Kernel API Manual, brought to you by the file path ./drivers/gpu/drm/amd/display/... and dated October 2026 — see you in the group chat, bestie 🧚‍♀️💜