Hi Tobias,
do you have CONFIG_DMA_CMA set in your config? If not please make sure
you have this commit in your testing tree, and if the problem still
persists it would be a little odd and we'd have to dig deeper:
commit dd3dcede9fa0a0b661ac1f24843f4a1b1317fdb6
Author: Nicolin Chen <nicoleotsuka@xxxxxxxxx>
Date: Wed May 29 17:54:25 2019 -0700
dma-contiguous: fix !CONFIG_DMA_CMA version of dma_{alloc, free}_contiguous()
