ttm_bo_kmap(9)

📦 version 7.3.1, in nixpkgs unstable

💅 ttm_bo_kmap

okay so bestie, welcome to the ttm_bo_kmap(9) glow-up — this is straight out of the Kernel API Manual and it's lowkey one of those little glue functions that holds the whole graphics subsystem together. no cap.

✨ NAME ✨

ttm_bo_kmap — and yeah, the source tarball literally leaves this line empty 🙈 so we're not gonna make up a tagline for it. main character with no bio, truly iconic.

🌸 SYNOPSIS 🌸

int ttm_bo_kmap (struct ttm_buffer_object *bo , unsigned long start_page
, unsigned long num_pages , struct ttm_bo_kmap_obj *map );

🎀 ARGUMENTS 🎀

  • bo — the buffer object in question, aka the whole reason we're here 💖
  • start_page — the first page to map. like where the mapping starts, bestie.
  • num_pages — how many pages we're mapping. the count. the vibe. the quantity.
  • map — pointer to a struct ttm_bo_kmap_obj that represents the map 🫶

🦋 DESCRIPTION 🦋

so what this does is it sets up a kernel virtual mapping to the data sitting in the buffer object — and it pulls that off using ioremap, vmap or kmap. which one? whichever, that's the vibe ✨.

once that's done you can call the ttm_kmap_obj_virtual function to grab a virtual address pointing at the data. literally the payoff. that's how you actually touch the bytes 👑

and the return values, because obviously:

  • -ENOMEM — out of memory 😭
  • -EINVAL — invalid range 💀
bestie pls check your range before you call this. -EINVAL is not the moment we want.

🌈 SEE ALSO 🌈

the whole squad, all linked from the kernel file ./drivers/gpu/drm/ttm/ttm_bo_util.c — go read them, iykyk:

anyway that's the whole page, mwah 💋 — this one lives under ./drivers/gpu/drm/ttm, dated October 2026, and it's filed as ttm_bo_kmap(9). slay, go map some pages 🧚💜

📦 where this page comes from