amdgpu_atpx_switch_start(9)

💅 amdgpu_atpx_switch_start — kernel API manual, but make it make sense 🎀

okay bestie, so this page is amdgpu_atpx_switch_start(9) from the kernel API manual, and it's literally the "hey sbios, we're starting the switch" text message of the AMD GPU world. short page, but she ate. let's go ✨

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🌸 NAME 🌸

amdgpu_atpx_switch_start — notify the sbios of a GPU switch

like, that's the whole job. she's a notifier. she notifies. periodt. 💅

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🦋 SYNOPSIS 🦋

int amdgpu_atpx_switch_start (struct amdgpu_atpx *atpx , u16 mux_id );

that signature is exactly what it is, character for character, don't come for me 🫶

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✨ ARGUMENTS ✨

• atpx — the atpx info struct. that's it, that's the whole description. she's the little info bundle you hand over so the function knows what's up 💖
• mux_id — the mux state, and this one matters bestie: 0 = integrated GPU, 1 = discrete GPU. two options, no in-between, no vibe check needed 👑

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🔥 DESCRIPTION 🔥

okay so the ~lore~: this function executes the ATPX_FUNCTION_GRAPHICS_DEVICE_SWITCH_START_NOTIFICATION ATPX function — yes that's the whole name, yes it's a mouthful, yes it's giving "my mom named me after a wifi password" — and what it does is notify the sbios that a switch between the discrete GPU and integrated GPU has begun. this applies to all asics, no cap, every single one 🌈

and the returns? 0 on success, error on failure. iconic. simple. no surprises. the way that a return value should be fr fr 💀

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👑 SEE ALSO 👑

the kernel file lives right here, like this:

./drivers/gpu/drm/amd/amdgpu/amdgpu_atpx_handler.c

and here's the whole friend group, all of them, not skipping a single one because that would be rude 😤

amdgpu_atpx_call(9), amdgpu_atpx_parse_functions(9), amdgpu_atpx_validate(9), amdgpu_atpx_verify_interface(9), amdgpu_atpx_set_discrete_state(9), amdgpu_atpx_switch_disp_mux(9), amdgpu_atpx_switch_i2c_mux(9), amdgpu_atpx_switch_end(9), amdgpu_atpx_switchto(9), amdgpu_atpx_power_state(9), amdgpu_atpx_pci_probe_handle(9), amdgpu_atpx_init(9), amdgpu_atpx_get_client_id(9), amdgpu_atpx_detect(9), amdgpu_register_atpx_handler(9), amdgpu_unregister_atpx_handler(9)

like look at that roster. main character energy from every last one of them 🧚💜

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🍓 sign-off 🍓

and that's the page!! source path is ./drivers/gpu/drm/amd/amdgpu, dated October 2026, filed under amdgpu_atpx_switch_start(9) — mwah, go switch some GPUs responsibly bestie, ily, bye!! 😭💖🫶