Fix/hip apu host buffer

[Victor-Loos]

Overview

Fixes a regression after #24233, which restored HIP integrated GPU detection. On my AMD APU, this also made the ROCm host-buffer path available for HIP integrated GPUs. With that path enabled, prompt input appears corrupted: chat templates and system prompts can be ignored, and generated output becomes garbage.

This change keeps integrated GPU detection/reporting intact, but disables host-buffer exposure for HIP integrated GPUs.

Additional information

Tested locally on gfx1151 / RDNA3.5 APU with ROCm 7.14. The corrupted input/output issue is fixed with this patch.
The built-in web UI did not reproduce the issue when used first, but external harnesses like Pi and OpenCode do.

Requirements

• I have read and agree with the contributing guidelines
• AI usage disclosure: YES - I used AI assistance to review and patch the relevant code. I tested and reviewed the final change myself.

[pwilkin]

@liminfei-amd could you please take a look?

[liminfei-amd]

Thanks for the ping. I tested this on gfx1151 / ROCm 7.2.1. Before #24233, the host-buffer capability and factory were already enabled; the newly reachable behavior was supports_buft(ROCm_Host): false -> true.

The current patch fixes this conservatively, but disabling the factory reduced pp512 from 5857 to 1502 t/s. I suggest a narrower fix:

caps/factory = GGML_CUDA_NO_PINNED is not set
supports_buft(ROCm_Host) = caps/factory enabled && not a HIP integrated device

This keeps pinned staging/output buffers but prevents direct HIP APU computation on ROCm_Host. It retained 5725 t/s (97.7% of baseline). Could you test this variant with the exact Pi/OpenCode reproduction?

[Victor-Loos]

Thanks @liminfei-amd for the testing and for clarifying the narrower fix.

I tested your suggested variant with my setup, and it still fixes the issue. I've updated the PR accordingly.

As for performance, on my setup I didn't see any meaningful difference. Here are my llama-bench results with a Qwen3.6-35B-A3B model:

Version	pp512 (t/s)	tg128 (t/s)
Before	1165.42 ± 29.48	67.57 ± 0.87
Fix v1	1148.87 ± 23.64	67.76 ± 0.70
Fix v2	1144.09 ± 20.46	68.11 ± 0.74

Could you retest the updated version on your side and confirm whether it preserves the pp512 result you mentioned? If there's still a difference, could you share the exact command and model you used so I can try to reproduce it?

[flashburns]

Hello I ran into issues on my strix halo box and this PR fixes it. Step 3.7 Flash IQ4_XS will spam < in a loop at 4k+ context.
I had an agent bisect the issue and it traced it down to the same commit & PR. c7d8722

I have now tested this pull request on my box and its solved.