STRUCT SND_FIREWIRE_EVENT_FF400_MESSAGE(9)

💅 struct snd_...f400_message(9)

okay bestie, so this is a page straight out of the Kernel API Manual and it's literally all about a little struct that carries messages from your Fireface 400 when you're out here twiddling the hardware knob. yes, the physical one. with your hands. iconic behaviour tbh 🎛️✨

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✨ NAME ✨

struct snd_firewire_event_ff400_message — the container for message from Fireface 400 when operating hardware knob. that's it, that's the whole vibe 🫶

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🦋 SYNOPSIS 🦋

here's the shape of her, copy it exactly bestie, no freestyling:

struct snd_firewire_event_ff400_message {
    unsigned int type;
    unsigned int message_count;
    struct {
      __u32 message;
      __u32 tstamp;
    } messages[];
 };

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🌸 Members 🌸

• type — fixed to SNDRV_FIREWIRE_EVENT_FF400_MESSAGE. like, it does not change. it knows who it is. main character energy fr 🔥
• message_count — the number of messages. that's it, that's the whole job 💅
• messages — array of message_count messages. yes, the array is literally named the same as the thing it holds. we love a self-aware queen 👑
• messages.message — the messages expressing hardware knob operation. this is the actual "you turned the knob" tea ☕
• messages.tstamp — the isochronous cycle at which the request subaction of asynchronous transaction was sent to deliver the message. ngl that's a mouthful, so lemme break it down: it has a 16-bit unsigned integer value. the higher 3 bits of value expresses the lower three bits of second field in the format of CYCLE_TIME, up to 7. the remaining 13 bits express cycle field up to 7999. yes, 3 + 13 = 16, the math is mathing ✨

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💖 Description 💖

the structure expresses message transmitted by Fireface 400 when operating hardware knob. literally that's the whole plot. hardware knob gets touched → Fireface 400 sends a message → this struct is the little envelope it arrives in 💌

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🎀 SEE ALSO 🎀

• Kernel file ./include/uapi/sound/firewire.h struct snd_firewire_motu_register_dsp_meter(9), struct snd_firewire_motu_register_dsp_parameter(9), struct snd_firewire_motu_command_dsp_meter(9)

go read those next, they're the friend group of this struct and they all slay in their own way 🌈

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and that's the page bestie!! 🧚 this one lives at ./include/uapi/sound and the date on the tag is October 2026, and yeah the whole thing is filed under struct snd_...f400_message(9) in case you need to find her again. mwah, study well, drink water, and remember: never guess at struct layout, only read the header 💜🍓🫶