cs_amp_set_...bration_data(9)

📦 version 7.3.1, in nixpkgs unstable

💫 cs_amp_set_efi_calibration_data — from the Kernel API Manual ✨

okay so bestie, this is from the Kernel API Manual (section 9, kernel API vibes 💅) and it's literally the page for cs_amp_set_...bration_data(9) — yes the title is truncated like that, that's just how it's printed, don't come for me 🫶. Anyway, it's giving "write a calibration data entry to EFI" and honestly it slays.

✨ NAME ✨

cs_amp_set_efi_calibration_data — write a calibration data entry to EFI. that's it, that's the whole job, and she does it 💖

🌸 SYNOPSIS 🌸

int cs_amp_set_efi_calibration_data (struct device *dev , int amp_index
, int num_amps , const struct cirrus_amp_cal_data *in_data );

like, four args, one int back, no cap 🦋

🎀 ARGUMENTS 🎀

  • dev — the struct device of the caller. your device, your business ✨
  • amp_index — the entry index to use, or -1 to use any available slot. -1 is the "idc just find me a spot" energy 🙈
  • num_amps — the maximum number of amps to reserve slots for, or -1 to ignore. so -1 means don't reserve, just vibe 🌈
  • in_data — the struct cirrus_amp_cal_data entry to be written to EFI. this is the actual data getting shipped off to EFI-land 💌

🔥 DESCRIPTION 🔥

okay so here's the tea, and it's a whole priority list 👑

if a Vendor-specific variable exists, it will be updated. else if the Cirrus variable exists, it will be updated. else the Cirrus variable will be created. periodt — that's the order, don't mess with the order 💅

now, if amp_index >= 0, the data gets placed in this entry of the calibration data array, overwriting what was in that entry 😭 (yes, straight up replacing it). and any other entries with the same calTarget will be marked empty. so like, one target, one slot, we don't do duplicates here 🫶

if amp_index < 0 and in_data->calTarget matches any existing entry, that entry will be overwritten. else, the first available free entry will be used — and if there are no free entries at all, it extends the size of the EFI variable 🔥 iconic problem-solving honestly.

if num_amps > 0, the EFI variable will be sized to contain at least this many calibration entries, with any new entries marked empty. lowkey just setting aside the seats before the guests arrive 🎀

⭐ RETURN ⭐

  • 0 — the write was successful. we love a clean win 🌟
  • -EFBIG — space could not be made in the EFI file to add the entry. tragic, genuinely 😭
  • -EACCES — it was not possible to read or write the EFI variable. access said no ma'am 💀

🦋 SEE ALSO 🦋

Kernel file ./sound/soc/codecs/cs-amp-lib.c — that's the home base bestie ✨

go read them, iykyk 👑💜

and that's the whole page, bestie 🫶 this cutie lives in ./sound/soc/codecs, dated October 2026, and she's listed under cs_amp_set_...bration_data(9) — stan her, she writes calibration data to EFI and she does it flawlessly 💖✨🎀

📦 where this page comes from