amdgpu_doorb...index_on_bar(9)

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

okay so this is a page straight out of the Kernel API Manual and the star of the show is amdgpu_doorbell_index_on_bar. yes it's a long name. yes it's iconic. we move.

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✨ NAME ✨

amdgpu_doorbell_index_on_bar — literally just goes and finds a doorbell's absolute offset in BAR. that's the whole job. she's focused, she's employed, she slays. 🔔

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🌸 SYNOPSIS 🌸

uint32_t amdgpu_doorbell_index_on_bar (struct amdgpu_device *adev ,
struct amdgpu_bo *db_bo , uint32_t doorbell_index , uint32_t db_size );

that's the signature, copy it exactly, no notes, don't @ me 🫶

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🎀 ARGUMENTS 🎀

• adev — an amdgpu_device pointer. the main character of the whole amdgpu situation, honestly.
• db_bo — the doorbell object's bo. yes, bo. that's what it's called. we don't question the naming conventions of our elders.
• doorbell_index — the doorbell's relative index inside this particular doorbell object. relative, bestie. keep that in mind or you'll be lost.
• db_size — the doorbell size, and it's in byte (singular, as the ancestors wrote it 💀).

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🦋 DESCRIPTION 🦋

so what does it actually do? it returns the doorbell's absolute index in BAR. that's it. that's the vibe. in goes the relative index, out comes the absolute one. glow-up complete. ✨

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💜 SEE ALSO 💜

peep these, they're all in the same friendship group:

• the kernel file ./drivers/gpu/drm/amd/amdgpu/amdgpu_doorbell_mgr.c
• amdgpu_mm_rdoorbell(9)
• amdgpu_mm_wdoorbell(9)
• amdgpu_mm_rdoorbell64(9)
• amdgpu_mm_wdoorbell64(9)
• amdgpu_doorbell_create_kernel_doorbells(9)
• amdgpu_doorbell_init(9)
• amdgpu_doorbell_fini(9)

go read the whole friend group, iykyk 📚

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live from ./drivers/gpu/drm/amd/amdgpu, dated October 2026, this has been amdgpu_doorb...index_on_bar(9) 🎀 thanks for coming to my ted talk, mwah, no cap, bye bestie 💖🔥