compute_pre_rec_first_hdl(9)

💅 compute_pre_rec_first_hdl — the manual page, but make it make sense

okay so bestie, we're in the Kernel API Manual for compute_pre_rec_first_hdl(9) and honestly this one is short and sweet — like, the function literally just computes the first hdl position of the pre and rec swath given the input params. that's the whole vibe. 🎀

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(yeah that asterisk line was just sitting there in the original, so i'm preserving it. it's giving divider energy. iconic.)

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✨ SYNOPSIS ✨

void compute_pre_rec_first_hdl (const struct
dml2_core_calcs_calculate_alternate_params *p , bool chroma , unsigned
int stream_idx , unsigned int plane_idx , double *pre_first_hdl_out ,
double *rec_first_hdl_out );

it returns void, so like... no return value, no crumbs, no nothing. it just does the thing and writes out through the pointers. periodt. 💅

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🌸 ARGUMENTS 🌸

okay bestie so here's the thing — the original page says -- undescribed -- for every single one of these. not me making that up, that's literally what the source says. so i'm gonna give you exactly that, but with love. 🫶

• p — -- undescribed -- 🙈
• chroma — -- undescribed -- 🙈
• stream_idx — -- undescribed -- 🙈
• plane_idx — -- undescribed -- 🙈
• pre_first_hdl_out — -- undescribed -- 🙈
• rec_first_hdl_out — -- undescribed -- 🙈

ngl, the docs are leaving us on read here. all six params are marked -- undescribed -- in the original, so i'm not about to invent lore that isn't there. iykyk. 💀

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🦋 SEE ALSO 🦋

so true bestie, go read the source if you want the juicy details:

• Kernel file: ./drivers/gpu/drm/amd/display/dc/dml2_0/dml21/src/dml2_core/dml2_core_dcn6_calcs_dchub.c
• get_plane_params(9)
• calculate_copy_swaths(9)
• calculate_alt_copy_time_us(9)
• calculate_ub_copy_size_per_plane_per_dpp_per_svp(9)
• calculate_swath_params(9)

like, the whole swath-computing friend group. the way they all reference each other... main character energy, fr fr. 🌈

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✨ sign-off time ✨

this little beauty lives over in ./drivers/gpu/drm/amd/display/..., and the page is stamped October 2026 with compute_pre_rec_first_hdl(9) in the footer. so like, future-dated manpage. obsessed. 👑💖 slay responsibly, and remember: keep every hdl where it belongs. ⭐