STRUCT PD_MESSAGE(9)

💖 struct pd_message(9) 💖

okay so bestie, welcome to the Kernel API Manual — yes that's the manual name, we're fancy now — and today's main character is struct pd_message, aka a PD message exactly as it shows up on the wire ✨. Like, this is the glow-up form, the one the hardware actually sees, no cap 🫶.

🌸 SYNOPSIS 🌸

struct pd_message {
    __le16 header;
    union {
      __le32 payload[PD_MAX_PAYLOAD];
      struct pd_chunked_ext_message_data ext_msg;
    };
 };

look at her. she's so simple. she's so iconic. 💅

🎀 Members 🎀

• header — the PD message header 💫. yeah that's it, that's the whole vibe.
• {unnamed_union} — it's anonymous 🫥. no name, no problem, she doesn't need one to slay.
• payload — the PD message payload 🍓, laid out as __le32 payload[PD_MAX_PAYLOAD] inside that anonymous union.
• ext_msg — the PD message chunked extended message data 🌈, hanging out in the same anonymous union as payload, sharing the space like good roommates.

lowkey the union thing is the whole point — payload and ext_msg are the same bytes, bestie. pick your interpretation, don't pick both 👑

🦋 SEE ALSO 🦋

• Kernel file ./include/linux/usb/pd.h struct
• pd_chunked_ext_message_data(9)
• struct sink_caps_ext_msg(9)
• BSDO(9)

go read those next, fr fr, they're all connected iykyk 🔥

and that's the whole page, periodt 💜. this came to you from ./include/linux/usb, dated October 2026, footer supremacy 👑 — signed off with the same struct pd_message(9) energy we started with 🧚‍♀️✨