STRUCT SSAM_CDEV_REQUEST(9)

💅 struct ssam_cdev_request(9) — the Kernel API Manual, bestie edition ✨

okay so picture this: it's section 9 of the Kernel API Manual, and the star of the show is struct ssam_cdev_request — literally the IOCTL argument for a Controller request 🎀 she's the little envelope you hand the kernel when you want it to go talk to the Surface Aggregator for you. main character energy fr fr.

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✨ SYNOPSIS ✨

no cap, here's the whole shape of her — copy it exactly, she's picky:

struct ssam_cdev_request {
    __u8 target_category;
    __u8 target_id;
    __u8 command_id;
    __u8 instance_id;
    __u16 flags;
    __s16 status;
    struct {
      __u64 data;
      __u16 length;
      __u8 __pad[6];
    } payload;
    struct {
      __u64 data;
      __u16 length;
      __u8 __pad[6];
    } response;
 };

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🌸 MEMBERS 🌸

she's got options, and every single one of them matters. let's do a vibe check on each 👑

• target_category — the target category of the SAM request 🎯 like, which hood we're pulling up on.
• target_id — the target ID of the SAM request 💫 the specific address inside that hood.
• command_id — the command ID of the SAM request 📨 what we're actually asking her to do.
• instance_id — the instance ID of the SAM request 🧚 the instance in question, iykyk.
• flags — request flags, and yes she has her own little enum — go peek at enum ssam_cdev_request_flags 🚩.
• status — request status, and heads up bestie: this one is an output 📤 it's what she tells you.
• payload — request payload, i.e. the input data you're sending in 📥💖

🍓 payload sub-members

• payload.data — pointer to the request payload data. just a pointer, she's not carrying the data herself, she's pointing at it 🫵
• payload.length — length of the request payload data, measured in bytes 📏 no vibe-based units, actual bytes.

🦋 response sub-members

• response — request response, the output data coming back atcha 📬
• response.data — pointer to the response buffer. again: pointing, not holding 💅
• response.length — and this one is a lil sneaky, she pulls double duty 😭
  • On input: the capacity of the response buffer, in bytes — like, how much room she's allowed to fill.
  • On output: the length of the request response — the number of bytes in the buffer that are actually used. so she comes back telling you how much of the space she really used. iconic honestly.

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🌈 SEE ALSO 🌈

go read these next, they're all linked in the group chat:

• Kernel file ./include/uapi/linux/surface_aggregator/cdev.h
• enum ssam_cdev_request_flags(9)
• struct ssam_cdev_notifier_desc(9)
• struct ssam_cdev_event_desc(9)
• struct ssam_cdev_event(9)

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⭐ reminder bestie: status is output, payload is input, and response.length is both directions. do NOT get them mixed up or the kernel will simply not be slaying 💀

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and that's the whole page 🫶 straight out of ./include/uapi/linux/surface_a..., dated October 2026, struct ssam_cdev_request(9) — periodt. 💜✨