STRUCT USB_COMPOSITE_DEV(9)

✨ STRUCT USB_COMPOSITE_DEV(9) ✨

okay so bestie, gather round 💖 this is the struct usb_composite_dev page from the Kernel API Manual — and yes it's literally the main character of composite USB gadget land 👑

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🌸 NAME 🌸

struct usb_composite_dev — represents one composite usb gadget 🦋

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🎀 SYNOPSIS 🎀

struct usb_composite_dev {
    struct usb_gadget               *gadget;
    struct usb_request              *req;
    struct usb_request              *os_desc_req;
    struct usb_configuration        *config;
    u8 qw_sign[OS_STRING_QW_SIGN_LEN];
    u8 b_vendor_code;
    struct usb_configuration        *os_desc_config;
    unsigned int                    use_os_string:1;
    u16 bcd_webusb_version;
    u8 b_webusb_vendor_code;
    char landing_page[WEBUSB_URL_RAW_MAX_LENGTH];
    unsigned int                    use_webusb:1;
    unsigned int                    setup_pending:1;
    unsigned int                    os_desc_pending:1;
 };

like, that's the whole struct, no notes 💅

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🧚 Members 🧚

• gadget — read-only, and it abstracts the gadget's usb peripheral controller ✨
• req — used for control responses; the buffer is pre-allocated 🫶
• os_desc_req — used for OS descriptors responses; the buffer is pre-allocated, same energy 💖
• config — the currently active configuration 👑
• qw_sign — the qwSignature part of the OS string 🎀
• b_vendor_code — the bMS_VendorCode part of the OS string 🦋
• os_desc_config — the configuration to be used with OS descriptors 🌸
• use_os_string — false by default, and interested gadgets set it ⭐
• bcd_webusb_version — 0x0100 by default, it's the WebUSB specification version 🌈
• b_webusb_vendor_code — 0x0 by default, the vendor code for WebUSB 💅
• landing_page — empty by default, this is the landing page to announce in WebUSB 🍓
• use_webusb — false by default, interested gadgets set it 🔥
• setup_pending — true when a setup request is queued but not completed 😭
• os_desc_pending — true when an os_desc request is queued but not completed 💀

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💜 Description 💜

One of these devices is allocated and initialized before the associated device driver's bind is called. that's it, that's the vibe, no cap 🧚✨

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🔥 SEE ALSO 🔥

• Kernel file ./include/linux/usb/composite.h struct usb_os_desc_ext_prop(9), struct usb_os_desc(9), struct usb_os_desc_table(9), struct usb_function(9), struct usb_configuration(9), struct usb_composite_driver(9), module_usb_composite_driver(9) 🫶

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okay that's the whole page bestie, go forth and composite 💖👑

sourced from ./include/linux/usb, dated October 2026, from the one and only struct usb_composite_dev(9) — slay, periodt ✨🎀