r535_gsp_msg_libos_print(9)

💖 r535_gsp_msg_libos_print(9) 💖

okay bestie, welcome to the Kernel API Manual — this one's literally called r535_gsp_msg_libos_print(9) and it's all about catching log messages from the PMU. it's giving "tiny function, big responsibility" energy ngl ✨

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🌸 NAME 🌸

r535_gsp_msg_libos_print — capture log message from the PMU 🫶

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🎀 SYNOPSIS 🎀

int r535_gsp_msg_libos_print (void *priv , u32 fn , void *repv , u32 repc );

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✨ ARGUMENTS ✨

• priv — the gsp pointer, bestie. that's the one.
• fn — function number (ignored 🙈 like, we literally do not look at it)
• repv — pointer to libos print RPC
• repc — message size

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🦋 DESCRIPTION 🦋

So here's the vibe: this one gets called when we receive a UCODE_LIBOS_PRINT event RPC from GSP-RM. That RPC is carrying the contents of the libos print buffer from the PMU. And lowkey? It's typically only written to when the PMU encounters an error 😭 so like, if you're seeing this pop off, something probably went sideways.

Technically — and I do mean technically — this RPC can be used to pass print buffers from any number of GSP-RM engines. But fr fr, we only expect to receive them for the PMU. that's the whole situation.

And for the PMU specifically: the buffer is 4K in size and the RPC always contains the full contents. no partial sends, no crumbs, the whole thing. periodt. 💅

heads up bestie: this page is describing an RPC handler, so the "typical" behaviour (only written on PMU error) is not a guarantee you should build on — the description says typically, and it also says the RPC can carry buffers from other engines in principle, even though only the PMU is expected.

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💜 SEE ALSO 💜

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

• 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)
• struct rpc_ucode_libos_print_v1e_08(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 the whole page, bestie 💖 this came to you from ./drivers/gpu/drm/nouveau/nvkm... and it's dated October 2026 — go forth and read your PMU logs, you iconic main character 🎀👑🌸