STRUCT FW_CDEV_START_ISO(9)

👑 struct fw_cdev_start_iso(9) 👑

okay bestie, so this is straight out of the Kernel API Manual, and it's the little struct that tells your FireWire isochronous stream go time 💅 like, literally the "start transmitting / start receiving" button in struct form. no cap.

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✨ NAME ✨

struct fw_cdev_start_iso — start an isochronous transmission or reception 🦋

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🌸 SYNOPSIS 🌸

struct fw_cdev_start_iso {
    __s32 cycle;
    __u32 sync;
    __u32 tags;
    __u32 handle;
 };

look at her. four fields. absolute main character energy 👑

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🎀 Members 🎀

okay so let's meet the squad, one member at a time 🫶

• cycle — the cycle in which to start the I/O, periodt. and here's the rule, bestie: if cycle is greater than or equal to 0, the I/O will start on that cycle. that's it, that's the vibe 🌈
• sync — this one decides the value you wait for on receive packets that have the FW_CDEV_ISO_SYNC bit set. it's giving "what am I looking for" energy ✨
• tags — the tag filter bit mask. ⚠️ heads up: this is only valid for isochronous reception — it determines the tag values for which packets will be accepted. use the FW_CDEV_ISO_CONTEXT_MATCH_* macros to set tags, iykyk 💅
• handle — the isochronous context handle, like, the within which you transmit or receive. your little VIP pass into the right context 🎟️

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🔥 SEE ALSO 🔥

first up, the file itself lives in the kernel at ./include/uapi/linux/firewire-cdev.h — go read the source, it's iconic 📖

and now the whole friend group, fr fr, every single one of them:

• struct fw_cdev_event_common(9)
• struct fw_cdev_event_bus_reset(9)
• struct fw_cdev_event_response(9)
• struct fw_cdev_event_response2(9)
• struct fw_cdev_event_request(9)
• struct fw_cdev_event_request2(9)
• struct fw_cdev_event_request3(9)
• struct fw_cdev_event_iso_interrupt(9)
• struct fw_cdev_event_iso_interrupt_mc(9)
• struct fw_cdev_event_iso_resource(9)
• struct fw_cdev_event_phy_packet(9)
• struct fw_cdev_event_phy_packet2(9)
• union fw_cdev_event(9)
• struct fw_cdev_get_info(9)
• struct fw_cdev_send_request(9)
• struct fw_cdev_send_response(9)
• struct fw_cdev_allocate(9)
• struct fw_cdev_deallocate(9)
• struct fw_cdev_initiate_bus_reset(9)
• struct fw_cdev_add_descriptor(9)
• struct fw_cdev_remove_descriptor(9)
• struct fw_cdev_create_iso_context(9)
• struct fw_cdev_set_iso_channels(9)
• struct fw_cdev_iso_packet(9)
• struct fw_cdev_queue_iso(9)
• struct fw_cdev_stop_iso(9)
• struct fw_cdev_flush_iso(9)
• struct fw_cdev_get_cycle_timer(9)
• struct fw_cdev_get_cycle_timer2(9)
• struct fw_cdev_allocate_iso_resource(9)
• struct fw_cdev_send_stream_packet(9)
• struct fw_cdev_send_phy_packet(9)
• struct fw_cdev_receive_phy_packets(9)

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ngl bestie, tags being reception-only is the one gotcha here — don't come for me if you set it on a transmit context, I warned you 😭

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okay that's the whole page!! mwah 💖 this one's from ./include/uapi/linux, dated October 2026 — catch you in the next manpage, bestie, slay 🧚‍♀️🌟