CMPCI(4)

📦
version 11.0 · 2 versions
, in nixpkgs unstable

💖 NAME 💖

okay bestie, welcome to the CMPCI(4) page from the Kernel Interfaces Manual — aka cmpci, the C-Media CMI8x38 audio device driver, and she is literally the main character 💅✨

✨ SYNOPSIS ✨

here's how she shows up, no cap:

cmpci* at pci? dev ? function ?
audio* at audiobus?
mpu*   at cmpci?
opl*   at cmpci? flags 1

🌸 DESCRIPTION 🌸

okay so the cmpci device driver supports C-Media CMI8x38 based sound cards 🎀

the device has SPDIF input/output interfaces, a 16bit CODEC with analog mixer, an OPL3 FM Synthesizer, and an MPU401 compatible MIDI I/O port interface. it's giving iconic, honestly 🦋

🎛️ MIXER DEVICE 🎛️

you can access the mixer device of the cmpci driver via the mixerctl(1) command. the complex structure is analyzed as follows — buckle up bestie, she's a lot but she's worth it 💜

       SPDIF in  ----------------------
       #1(coax)->|spdin1              |  R    -----------------------
       #2(opt)-->|spdin2  spdif.input |--*->--|spdin   spdif.output |--> SPDIF
              -->|spdout              |  | -->|playback             |    output
              |  ----------------------  | |  -----------------------
              --------------------<------+-*
            ---------<-------------------+-+----------------------------------
            |  ------------------------  | |   -----------------------       |
            -->|legacy  spdif.output. |--+-*-->|spdout               |       |
            -->|wave    playback      |  ----->|spdin  spdif.monitor |----   |
            |  ------------------------     NC-|off                  |   |   |
            ---------<-- spdif                 -----------------------   |   |
                -------+------- dac ------------    -----------------    v   |
       wave  -->|playback.mode|---->|inputs.dac|-*->|inputs.dac.mute|->----- |
       playback ---------------     ------------ R  -----------------  | + | |
                         -----------------     ---------------------   |mix| |
       FM synthesizer -->|inputs.fmsynth |--*->|inputs.fmsynth.mute|-->----- |
                         -----------------  R  ---------------------     *->--
       CD        ----------------------   ---------------------------    v
       LINE-IN ->|inputs.{cd,line,aux}|-*>|inputs.{cd,line,aux}.mute|->-----
       AUX       ---------------------- R ---------------------------  |   |
                 ------------------                                    |   |
       PC-SPK -->| inputs.speaker |----------------------------------->| + |
                 ------------------                                    |   |
                 -------------------  ------------  -----------------  |mix|
       MIC --*-->|inputs.mic.preamp|->|inputs.mic|->|inputs.mic.mute|->|   |
             |   -------------------  ------------  -----------------  -----
             |   ------------   -----------------                       |
             --->|record.mic|-->|               |                       v
                 ------------   | record.source |-->to         -----------
                           *R-->| (select, mix) |   recording  |outputs.*|-->
                                -----------------              ----------- SPK
                                                                        (front)
lowkey important: the 2nd SPDIF input exists only on CMI8738/PCI-6ch versions. don't @ me if your card doesn't have it 🫶

📸 MIXER EXAMPLES 📸

here are examples about wave playback and SPDIF input/output ports — copy these exactly, they're load-bearing bestie 💖

🌈 Playback to speaker, SPDIF input to SPDIF output

mixerctl -w playback.mode=dac spdif.output=spdin
spdif.monitor=off

🌈 Playback to SPDIF output, SPDIF input to speaker

mixerctl -w playback.mode=spdif spdif.output=playback
spdif.output.playback=wave spdif.monitor=spdin

🌈 SPDIF input to both SPDIF output and speaker

mixerctl -w spdif.output=spdin spdif.monitor=spdin

🌈 Playback to both SPDIF output and speaker

mixerctl -w playback.mode=spdif spdif.output=playback
spdif.output.playback=wave spdif.monitor=spdout

🌈 Mix playback and SPDIF input to speaker

mixerctl -w playback.mode=dac spdif.monitor=spdin

🔗 SEE ALSO 🔗

go read these too, they're all part of the lore ✨

🕰️ HISTORY 🕰️

the cmpci device driver appeared in NetBSD 1.5 — vintage but still cute 🎀

💀 BUGS 💀

  • 4ch/6ch playback is not yet available — sad, I know 😭
  • Joystick port is not supported — 🙈
  • spdif.output.playback=legacy does not seem to work properly — 💀

this page is from Debian, dated June 22, 2005 — mwah, stay slaying bestie 💋✨

📦 where this page comes from