STRUCT TB_CTL(9)

🦋 struct tb_ctl — Thunderbolt control channel

okay bestie, so this is the kernel API manual page for struct tb_ctl(9) and it's genuinely giving "the nervous system of your Thunderbolt port" energy — like, this struct is the control channel itself. no cap. ✨

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💖 NAME

struct tb_ctl — Thunderbolt control channel 🎀

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⚡ SYNOPSIS

struct tb_ctl {
    struct tb_nhi *nhi;
    struct tb_ring *tx;
    struct tb_ring *rx;
    struct dma_pool *frame_pool;
    struct ctl_pkg *rx_packets[TB_CTL_RX_PKG_COUNT];
    struct mutex request_queue_lock;
    struct list_head request_queue;
    bool running;
    int timeout_msec;
    event_cb callback;
    void *callback_data;
    int index;
 };

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🌸 Members

okay so here's the cast of characters, main-character by main-character 👑

• nhi — pointer to the NHI structure. it's the link-up to the big boss, iykyk 🫶
• tx — the transmit ring. this is where stuff leaves 💅
• rx — the receive ring. and this is where stuff arrives 🎁
• frame_pool — DMA pool for control messages. lowkey the supply closet for control traffic ✨
• rx_packets — received control messages. the whole inbox, literally 📬
• request_queue_lock — lock protecting request_queue. it keeps the queue safe from chaos fr fr 🔒
• request_queue — list of outstanding requests. everything still waiting on a reply lives here 🕰️
• running — is the control channel running at the moment. a yes/no vibe check on the whole operation ⭐
• timeout_msec — default timeout for non-raw control messages. like "how long do we wait before we give up" energy, in milliseconds ⏳
• callback — callback called when hotplug message is received. something shows up, this gets called, everybody finds out 🔥
• callback_data — data passed to callback. the little care package handed over with it 🎀
• index — domain number. this will be output with the trace record. so like, its name tag when the trace log snaps a pic of it 📸

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🌈 SEE ALSO

• Kernel file ./drivers/thunderbolt/ctl.c
• tb_cfg_request_alloc(9)
• tb_cfg_request_get(9)
• tb_cfg_request_put(9)
• tb_cfg_request(9)
• tb_cfg_request_cancel(9)
• tb_cfg_request_sync(9)
• tb_ctl_alloc(9)
• tb_ctl_free(9)
• tb_ctl_start(9)
• tb_ctl_stop(9)
• tb_cfg_ack_notification(9)
• tb_cfg_ack_plug(9)
• tb_cfg_reset(9)
• tb_cfg_read_raw(9)
• tb_cfg_write_raw(9)
• tb_cfg_get_upstream_port(9)

go read them all bestie, it's a whole friend group 💜🫶

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that's the whole page, no notes 💅

and finally, the cute sign-off — this one's from ./drivers/thunderbolt, dated October 2026. slay, periodt. 🧚💖🌸