ccw_device_tm_start(9)

💅 ccw_device_tm_start — bestie's guide to the kernel API manual ✨

okay so you're in the Kernel API Manual 🎀 and the function we're stanning today is ccw_device_tm_start, which literally just... performs the start function. that's it, that's the vibe. let's get into it 🦋

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🌸 SYNOPSIS 🌸

int ccw_device_tm_start (struct ccw_device *cdev , struct tcw *tcw ,
       unsigned long intparm , u8 lpm );

like yes she takes four args and returns an int, we love a consistent queen 👑

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✨ ARGUMENTS ✨

• cdev — the ccw device you're doing the start function on. the main character of this operation, fr fr 🫶
• tcw — the transport-command word that's getting started. this is the thing actually being launched, no cap 🚀
• intparm — user-defined parameter that gets passed along to the interrupt handler. your little note-to-self, your iykyk handoff 💌
• lpm — mask of the paths to use. it's a u8, so keep it smol and correct 💅

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💖 DESCRIPTION 💖

Start the tcw on the given ccw device. that's the whole bit, genuinely 🌈

returns zero on success, and non-zero otherwise 😭 — so like, don't be out here checking for 1 specifically, just check for non-zero and you're slaying.

not me reminding you: zero = good, non-zero = go read something else 🙈

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🔥 SEE ALSO 🔥

the kernel file, first of all:

• Kernel file ./drivers/s390/cio/device_ops.c

and then the whole friend group, in order, because we do not skip anybody 👑:

• ccw_device_set_options_mask(9), ccw_device_set_options(9), ccw_device_clear_options(9), ccw_device_is_pathgroup(9), ccw_device_is_multipath(9), ccw_device_clear(9), ccw_device_start_timeout_key(9), ccw_device_start_key(9), ccw_device_start(9), ccw_device_start_timeout(9), ccw_device_halt(9), ccw_device_resume(9), ccw_device_get_ciw(9), ccw_device_get_path_mask(9), ccw_device_get_chp_desc(9), ccw_device_get_util_str(9), ccw_device_get_id(9), ccw_device_tm_start_timeout_key(9), ccw_device_tm_start_key(9), ccw_device_tm_start_timeout(9), ccw_device_get_mdc(9), ccw_device_tm_intrg(9), ccw_device_get_schid(9), ccw_device_pnso(9), ccw_device_get_cssid(9), ccw_device_get_iid(9), ccw_device_get_chpid(9), ccw_device_get_chid(9)

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and that's the page!! 🎀 sign-off time: this lil masterpiece lives in ./drivers/s390/cio, dated October 2026, and it's filed under ccw_device_tm_start(9). go forth and start those transport-command words, bestie 💜⭐