Created attachment 140585 [details]
dmesg with 0001-drm-amdgpu-pp-smu7-cache-smu-firmware-toc.patch

This patch makes resume work, attached is the dmesg output of boot + 3
suspend-resume cycles. Please note the powerplay error messages, followed
ultimately by a GPU reset.

Looking at the patch it seems similar to my workarond, in that the toc is
copied in one memcpy_toio (my patch uses plain memcpy, is there a difference
here, for memory mapped buffers?) instead of changing the toc in-place. And I
too see lots of powerplay errors if i apply my workaround.

Huge thanks for taking time to look into this!