cdx_mcdi_bus_master_enable(9)

💅 cdx_mcdi_bus_master_enable(9) — like, the whole glow-up

okay bestie, so this one lives in the Kernel API Manual and it's literally called cdx_mcdi_bus_master_enable — say that five times fast, i can't 😭 — and what it does is Set/Reset bus mastering for cdx device represented by bus_num:dev_num. that's the whole vibe. you're flipping bus mastering on or off for one specific device, and you point at that device with a bus number plus a device number. iconic little coordinate pair, no cap 🎀

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✨ SYNOPSIS ✨

int cdx_mcdi_bus_master_enable (struct cdx_mcdi *cdx , u8 bus_num , u8
dev_num , bool enable );

yup, that's the signature, copy it exactly, don't @ me 💅

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🌸 ARGUMENTS 🌸

• cdx — pointer to MCDI interface. that's your entry point, your main character, the thing you're talking through 🫶
• bus_num — Bus number. the first half of the address, slay.
• dev_num — Device number. the second half. together with bus_num they're giving bus_num:dev_num and that's who you're messing with ✨
• enable — Enable bus mastering if set, disable otherwise. so true = go go go 🔥, false = nope, not today 💀

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🌈 RETURN 🌈

• 0 on success — we love a clean zero, fr fr 👑
• <0 on failure — negative, sad, not the vibe 😭

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🦋 SEE ALSO 🦋

• Kernel file ./drivers/cdx/controller/mcdi_functions.h
• cdx_mcdi_get_num_buses(9) — how many buses we even got
• cdx_mcdi_get_num_devs(9) — and how many devs
• cdx_mcdi_get_dev_config(9) — the config lore
• cdx_mcdi_bus_enable(9) — bus on
• cdx_mcdi_bus_disable(9) — bus off
• cdx_mcdi_write_msi(9) — msi writing things
• cdx_mcdi_reset_device(9) — the factory-reset ahh moment
• cdx_mcdi_msi_enable(9) — msi on

all of these are also (9) sections, iykyk 🧚

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lowkey reminder: the see-also list above is exactly what's in the manpage — i'm not out here inventing extra friends for this function 💖

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and that's the tea, bestie 🍓 this page came from ./drivers/cdx/controller, dated October 2026, and it's filed under cdx_mcdi_bus_master_enable(9). go enable some bus mastering, you absolute legend 💜🌺