drm_gem_dma_create(9)

🌸 drm_gem_dma_create(9) — Kernel API Manual 🌸

Okay bestie, so this one is from the Kernel API Manual and it's called drm_gem_dma_create — and before you ask, yes, it's giving literally "allocate an object with the given size". No cap. 💅

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✨ SYNOPSIS ✨

struct drm_gem_dma_object * drm_gem_dma_create (struct drm_device *drm ,
size_t size );

That's the whole vibe — one function, two arguments, and it's gonna hand you back a pointer. 🫶

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🎀 ARGUMENTS 🎀

• drm — the DRM device. Like, the actual hardware situation you're working with. 🖥️
• size — the size of the object you wanna allocate. Yes, in bytes, and yes, you gotta tell it. 📏

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💖 DESCRIPTION 💖

So what does it do? It creates a DMA GEM object and allocates memory as the backing store. The allocated memory is gonna occupy a contiguous chunk of bus address space — that's the whole point, bestie. 🔥

Now, here's the tea on contiguity (and this part is important, so don't scroll past it):

• For devices that are directly connected to the memory bus, the allocated memory will be physically contiguous. Like, actually contiguous in physical memory. Slay. ✨
• For devices that access through an IOMMU, the allocated memory is not expected to be physically contiguous — because having contiguous IOVAs is sufficient to meet a device's DMA requirements. So it's fine, it's still valid, it's just not physically contiguous. No big deal. 💅

Lowkey, this distinction matters if you're debugging memory stuff, so keep it in mind, okay? 🧚

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👑 RETURN 👑

On success, you get a struct drm_gem_dma_object *. On failure, you get an ERR_PTR-encoded negative error code — so check that pointer, bestie, because it might be an error in disguise. 😭

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🌈 SEE ALSO 🌈

Here's the whole friend group — every single one of these is in the kernel file ./drivers/gpu/drm/drm_gem_dma_helper.c, and they're all linked from here:

• dma helpers(9)
• __drm_gem_dma_create(9)
• drm_gem_dma_create_with_handle(9)
• drm_gem_dma_free(9)
• drm_gem_dma_dumb_create_internal(9)
• drm_gem_dma_dumb_create(9)
• drm_gem_dma_get_unmapped_area(9)
• drm_gem_dma_print_info(9)
• drm_gem_dma_get_sg_table(9)
• drm_gem_dma_prime_import_sg_table(9)
• drm_gem_dma_vmap(9)
• drm_gem_dma_mmap(9)
• drm_gem_dma_prime_import_sg_table_vmap(9)

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And that's the whole page, bestie. This icon was dropped from ./drivers/gpu/drm in October 2026 — so you know it's fresh, it's official, and it's ready for you to use. Periodt. 💜🎀