DCN31X FPU MANIPULATION OVERVIEW(9)

✨ DCN31x FPU manipulation Overview ✨

ok so this is a page from the Kernel API Manual, section 9, and bestie it's literally all about keeping FPU stuff from leaking everywhere 💅

The DCN architecture relies on FPU operations, which require special compilation flags and the use of kernel_fpu_begin/end functions — and ideally, we want to avoid spreading FPU access across multiple files. Like, the dream is containment, not chaos 🫶

With this idea in mind, this file aims to centralize all DCN3.1.x functions that require FPU access in a single place. One file. That's the whole vibe. 🎀

Code in this file follows the following code pattern:

1. Functions that use FPU operations should be isolated in static functions. Keep 'em in their own little lane, no cap.
2. The FPU functions should have the noinline attribute to ensure anything that deals with FP register is contained within this call. The way that noinline just holds it in place 😭👑
3. All function that needs to be accessed outside this file requires a public interface that not uses any FPU reference. Outside world gets a clean door, not a peek at the FPU machinery.
4. Developers must not use DC_FP_START/END in this file, but they need to ensure that the caller invokes it before access any function available in this file. For this reason, public functions in this file must invoke dc_assert_fp_enabled;

fr fr on number 4 — must not means must not 😤 DC_FP_START/END does not go in this file, the caller has to invoke it before touching anything available here, and that's exactly why every public function in this file has to invoke dc_assert_fp_enabled; as a little safety check 🌸

🌈 SEE ALSO 🌈

• Kernel file ./drivers/gpu/drm/amd/display/dc/dml/dcn31/dcn31_fpu.c — go read it, it's giving main character energy 💖

ok that's the whole page, love u, bye 🦋💜 — this gem dropped from ./drivers/gpu/drm/amd/display/... in October 2026, DCN31x FPU manipulation Overview(9), and yes it's still the Kernel API Manual, periodt ✨🎀