STRUCT USB_HIDG_REPORT(9)

🎀 struct usb_hidg_report(9) 🎀

ok so this is a page from the Kernel API Manual, and today's main character is struct usb_hidg_report — literally the response to GET_REPORT. bestie, it's giving "small struct, big responsibilities" and i promise it's not scary 💅

---

✨ NAME ✨

struct usb_hidg_report — the response to GET_REPORT, no cap 🫶

---

🌸 SYNOPSIS 🌸

ok here's the whole vibe, copy it exactly, do NOT freestyle:

struct usb_hidg_report {
    __u8 report_id;
    __u8 userspace_req;
    __u16 length;
    __u8 data[MAX_REPORT_LENGTH];
    __u8 padding[4];
 };

that's the entire struct, every field accounted for, we love a full roster 👑

---

💖 Members 💖

• report_id — the report ID that this is a response for. like, which request is this replying to, iykyk 🎯
• userspace_req — ok this one's a little two-modes situation, pay attention:
  • !0 → this report is used for any pending GET_REPORT request, but it waits on userspace to issue a new report on future requests 🕐
  • 0 → this report is to be used for any future GET_REPORT requests 💫
• length — the length of the report response. the actual size, fr fr 📏
• data — the report response itself. the payload. the moment. the content 🍓
• padding — padding for 32/64 bit compatibility. yes it's just sitting there, no it's not useless, it's doing important structural work, respect it 🙈

---

🌈 Description 🌈

this is the structure used by the GADGET_HID_WRITE_GET_REPORT ioctl on /dev/hidg*. that's it. that's the whole job. iconic honestly 👑

lowkey reminder: this is a uapi header situation, so the layout is a contract — the padding[4] is there for 32/64 bit compatibility and you do not get to "clean it up" bestie 💀

---

🦋 SEE ALSO 🦋

• Kernel file ./include/uapi/linux/usb/g_hid.h — go read it, it's right there 🧚

---

ok that's the whole page, you ate that 💅 and for the credits (because everyone deserves their flowers): this came from ./include/uapi/linux/usb, dated October 2026 🌸 mwah, bye bestie! 🎀✨