STRUCT DWC2_TT(9)

✨ struct dwc2_tt(9) ✨

okay so this is from the Kernel API Manual and it's literally the cutest little struct — it's the dwc2 data that gets associated with a usb_tt 🫶

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💖 NAME 💖

struct dwc2_tt — the dwc2 data that's associated with a usb_tt, no cap

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🌸 SYNOPSIS 🌸

struct dwc2_tt {
    int refcount;
    struct usb_tt *usb_tt;
    unsigned long periodic_bitmaps[];
};

like... look at her. three members. iconic. 👑

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🎀 Members 🎀

• refcount — the number of Queue Heads (QHs) that are holding a reference to this thing. it's giving "how many besties are currently borrowing my hoodie" energy 🙈
• usb_tt — a pointer that points right back at the official usb_tt. a little link home, fr fr 🏠
• periodic_bitmaps — a bitmap that tracks which parts of the 1ms frame are already accounted for. each one is DWC2_ELEMENTS_PER_LS_BITMAP elements (so sizeof(long) times that, in bytes). the way that math just... works 💅

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🦋 Description 🦋

so this structure is stored in the hcpriv of the official usb_tt. that's it. that's the vibe. like it's literally just chillin' inside hcpriv and doing its job ✨

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⭐ SEE ALSO ⭐

• Kernel file ./drivers/usb/dwc2/hcd.h
• struct dwc2_host_chan(9)
• struct dwc2_hs_transfer_time(9)
• struct dwc2_qh(9)
• struct dwc2_qtd(9)
• dwc2_handle_hcd_intr(9)
• dwc2_hcd_stop(9)
• dwc2_hcd_is_b_host(9)
• dwc2_hcd_dump_state(9)

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bestie if you're poking at any of those structs above, go read their pages too — iykyk 🧚

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and that's the whole page, mwah 💋 this gem lives in ./drivers/usb/dwc2, it's the October 2026 edition, and the manual is struct dwc2_tt(9) — go read it, slay, periodt 🌈💜