sdma_v5_2_ring_emit_fence(9)

📦 version 7.3.1, in nixpkgs unstable

💅 sdma_v5_2_ring_emit_fence(9) — from the Kernel API Manual, bestie

okay so like… this is a kernel API page, not a command you type, but honestly the vibe is the same: somebody's gotta tell the GPU hardware what to do, and today that somebody is this function. sit down, hydrate, let's go 🫶

✨ NAME ✨

sdma_v5_2_ring_emit_fence — emits a fence on the DMA ring. that's it, that's the whole job. she shows up, she drops a fence packet, she leaves. main character energy fr 🔥

🌸 SYNOPSIS 🌸

void sdma_v5_2_ring_emit_fence (struct amdgpu_ring *ring , u64 addr ,
u64 seq , unsigned flags );

no return value (void), she just does the thing. ngl that's kind of iconic of her 💅

🎀 ARGUMENTS 🎀

four (4) things you gotta hand her, in order, no substitutions:

  • ring — your amdgpu ring pointer, aka the whole reason we're here. it's the ring bestie. the star of the show ✨
  • addr — an address. yes literally just "address". that's what the manual says, and I respect the brevity 😌
  • seq — the sequence number, which is the number that actually gets written out by the fence. lowkey the most important number in this whole function 👑
  • flags — fence-related flags. flags that relate to the fence. it's giving "you already know" iykyk 🙈

🦋 DESCRIPTION 🦋

so what actually happens? two (2) little packets get added to the ring, and each one has a job:

  1. the DMA fence packet — gets added to the ring so it can write out the fence seq number. the number goes in, the number goes out. slay ✨
  2. the DMA trap packet — also gets added to the ring, and it's there to generate an interrupt if needed. note the if needed, bestie — not always, only when it's needed. don't come for me, that's what the page says 💀

so: fence write + possible interrupt. simple, clean, ate and left no crumbs 🍓

🧚 SEE ALSO 🧚

first up, the source file herself — like if you wanna read the whole story, not just the trailer:

Kernel file ./drivers/gpu/drm/amd/amdgpu/sdma_v5_2.c

and then the whole rest of the sdma_v5_2 friend group, all of them, every single one (they all get the (9) treatment because they're kernel API pages too):

like… a whole ensemble cast, we love a franchise 🌈

okay that's the whole page, no notes 💜 before you go — this lil beauty lives in ./drivers/gpu/drm/amd/amdgpu, dated October 2026, from the Kernel API Manual (version header and all, we didn't skip it). go read a fence packet, stay hydrated, ily bye 🎀✨

📦 where this page comes from