STRUCT FWCTL_RPC_PDS(9)

💅 struct fwctl_rpc_pds(9) 💅

Okay so bestie, welcome to the Kernel API Manual — yes we're literally reading kernel headers for fun now, this is the era we're in, and honestly? iconic. Today's main character is struct fwctl_rpc_pds, and ngl the NAME section is giving mystery. There's no description after the dash. Nothing. Silence. The struct simply exists and refuses to explain itself. We respect the mystique. 🎀

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✨ SYNOPSIS ✨

Here's the whole shape of it, copied exactly, no cap:

struct fwctl_rpc_pds {
    struct {
      __u32 op;
      __u32 ep;
      __u32 rsvd;
      __u32 len;
      __aligned_u64 payload;
    } in;
    struct {
      __u32 retval;
      __u32 rsvd[2];
      __u32 len;
      __aligned_u64 payload;
    } out;
 };

See how it's split into two little nested structs, in and out? It's giving "request in, response out" energy. A whole conversation in one struct. Obsessed. 🦋

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🌸 Members 🌸

💖 in — rpc in parameters

The stuff you're sending. The ask. The "hey bestie can you do this for me" half of the struct.

• in.op — the requested operation code. This is the "what do you want me to do" field, fr fr.
• in.ep — the firmware endpoint to operate on. Like, which part of the firmware are we talking to. Pick your target wisely. 🎯
• in.rsvd — reserved. Hands off, it's not for you, leave it alone. 🙈
• in.len — length of payload data. How many bytes are we actually sending.
• in.payload — address of payload buffer. The actual goods, pointed at by address. __aligned_u64, so it's aligned, because of course it is. ✨

💜 out — rpc out parameters

The reply. The firmware's answer back to you. The group chat response after you send the message.

• out.retval — operation result value. Did it slay or did it flop? This tells you.
• out.rsvd — reserved. This one's rsvd[2], an array of two — so two whole reserved slots, and you're touching neither of them. 💀
• out.len — length of result data buffer. How much came back.
• out.payload — address of payload data buffer. Where the result actually lives. Also __aligned_u64. Consistent queen. 👑

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🫶 SEE ALSO 🫶

Go read these next, it's a whole little family:

• Kernel file ./include/uapi/fwctl/pds.h
• struct fwctl_info_pds(9)
• enum pds_fwctl_capabilities(9)

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Lowkey reminder: the rsvd fields are reserved. Don't be the one who writes into them. That's not a vibe, that's a bug. 😭

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And that's the page, bestie! Sourced from ./include/uapi/fwctl, dated October 2026, and signed off with the header struct fwctl_rpc_pds(9) because we always come full circle. 💫 Stay aligned, stay reserved, and go read your headers. 🧚💖