radeon_atpx_switch_i2c_mux(9)

💜 radeon_atpx_switch_i2c_mux(9)

okay so picture this: you're deep in the kernel API manual (section 9, bestie, the big-kid section) and you stumble onto radeon_atpx_switch_i2c_mux. Yeah. That one. Let's get into it 🫶

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✨ NAME ✨

radeon_atpx_switch_i2c_mux — the little function that flips the i2c/hpd mux. that's it. that's the whole job. iconic behavior, honestly 💅

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🌸 SYNOPSIS 🌸

int radeon_atpx_switch_i2c_mux (struct radeon_atpx *atpx , u16 mux_id );

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🦋 DESCRIPTION 🦋

so what does it actually do? it executes the ATPX_FUNCTION_I2C_MUX_CONTROL ATPX function, which switches the i2c/hpd mux back and forth between the discrete GPU and the integrated GPU — and yes, this works on all asics, no gatekeeping 💖

It returns 0 on success, and an error on failure. that's the whole vibe check: zero means slay, anything else means something went wrong 😭

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🎀 ARGUMENTS 🎀

• atpx — the atpx info struct. the main character of this whole operation 👑
• mux_id — the mux state. 0 = integrated GPU, 1 = discrete GPU. pick your fighter 🌈

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⭐ SEE ALSO ⭐

first up, the kernel file where all this lives, no cap:

• ./drivers/gpu/drm/radeon/radeon_atpx_handler.c

and the whole friend group of related calls, because they literally all roll together:

• radeon_atpx_call(9)
• radeon_atpx_parse_functions(9)
• radeon_atpx_validate(9)
• radeon_atpx_verify_interface(9)
• radeon_atpx_set_discrete_state(9)
• radeon_atpx_switch_disp_mux(9)
• radeon_atpx_switch_start(9)
• radeon_atpx_switch_end(9)
• radeon_atpx_switchto(9)
• radeon_atpx_power_state(9)
• radeon_atpx_pci_probe_handle(9)
• radeon_atpx_init(9)
• radeon_atpx_get_client_id(9)
• radeon_atpx_detect(9)
• radeon_register_atpx_handler(9)
• radeon_unregister_atpx_handler(9)

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and that's the page, bestie 🧚 sourced straight from ./drivers/gpu/drm/radeon, dated October 2026, and it's the radeon_atpx_switch_i2c_mux(9) manual page — go switch some muxes, you've got this 💅✨🍓