Re: [PATCH v4] drm/amd/pm: defer UCLK DPM on selected Apple Navi GPUs

[André Eikmeyer]

On Thu, 29 Oct 2026 17:57:49 -0400
Alex Deucher <alexdeucher@xxxxxxxxx> wrote:

> @Andre Eikmeyer I think this patch should fix your system as well.

Hi Alex,

I guess you have seen it already but the patch doesn't match the 16,1.
Its boards are 7340/020f and 7340/0210, and v4 only matches 0218, 0219
and 021a.

That hang is what I sent a fix for
https://lore.kernel.org/all/20261024162109.307247-1-dev@deq.rocks/

The VBIOS trains the UMC p-states at different frequencies the pp-table
lists. The SMU hangs as soon as UCLK switches into level 2. Deferring
the UCLK enable doesn't change the levels, so the hang just moves from
boot to later under load.

The two patches can coexist after a trivial rebase.

> ...your system...

I need to clarify here. I actually don't own a 16,1. But I maintain a
distro (KaiT2en) that specializes on T2 Macs. So the patches I develop
are extensively tested by the community before submitting. Atharwa is
part of this community. Ed is not, but Atharwa reviewed and tested the
code.

Best,
Andre