STRUCT RPC_UCODE_LIBOS_PRINT_V1E_08(9)

🎀 NAME 🎀

struct rpc_ucode_libos_print_v1e_08 — the RPC payload for libos print buffers 💖 (yes bestie, this is from the Kernel API Manual, section 9, and it's giving "tiny struct, big job" energy)

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✨ SYNOPSIS ✨

struct rpc_ucode_libos_print_v1e_08 {
    u32 ucode_eng_desc;
    u32 libos_print_buf_size;
    u8 libos_print_buf[];
};

okay so that's the whole shape of it, three members, no cap 🫶

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🌸 Members 🌸

• ucode_eng_desc — the engine descriptor 🧚 literally what it says on the tin
• libos_print_buf_size — the size of libos_print_buf[] 📏 so the buffer knows how big it is
• libos_print_buf — the actual buffer 🎀 the real one, the main character, the payload itself

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🦋 Description 🦋

So here's the tea ☕: the engine descriptor is split up into a 31:8 "class ID" and a 7:0 "instance ID". That's the bit-slicing, iykyk. And out of all of that? We only care about messages from PMU 💅 that's it, that's the whole vibe check.

ngl, everything else in that descriptor is just kind of there doing its thing — PMU messages are the only ones we're obsessed with 💀

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💜 SEE ALSO 💜

the kernel file in question, bestie:

• ./drivers/gpu/drm/nouveau/nvkm/subdev/gsp/rm/r535/gsp.c

and the whole friend group 🔥:

• nvkm_gsp_mem_ctor(9)
• struct registry_list_entry(9)
• add_registry(9)
• build_registry(9)
• clean_registry(9)
• strip(9)
• r535_gsp_rpc_set_registry(9)
• r535_gsp_msg_run_cpu_sequencer(9)
• r535_gsp_msg_libos_print(9)
• create_debugfs(9)
• r535_gsp_libos_debugfs_init(9)
• create_pte_array(9)
• r535_gsp_libos_init(9)
• nvkm_gsp_radix3_sg(9)
• r535_debugfs_shutdown(9)
• is_empty(9)
• r535_gsp_copy_log(9)
• r535_gsp_retain_logging(9)
• r535_gsp_libos_debugfs_fini(9)

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and that's a wrap, bestie 🎬 source is ./drivers/gpu/drm/nouveau/nvkm... and it's dated October 2026 — same page name, struct rpc_...print_v1e_08(9), slay 💅✨