Created attachment 143074 [details]
Image showing the rendering issues of TPH with radeonsi on OLAND

A friend of mine for whom I'm doing the Linux tech support has trouble playing Two Point Hospital (TPH) on his Oland XT GPU with radeonsi. With older versions of Mesa the game locked up the GPU after a while, therefore I built him a Mesa from Git, linked against LLVM 8 (see below for details on the complete stack). But with the Git version the game becomes completely unplayable, because most of the screen is rendered in black. Menus and some outlines are shown. See the attached picture my friend sent me for details on how this looks. [NB: I've been able to play TPH on my HAWAII PRO based system without any issues so far.]
He uses the radeon stack, due to the limitations of amdgpu with this GPU generation.

At <https://c.1und1.de/@519917343397118178/ZZXLY27mRj-iQZQsH0GFmQ> you'll find an apitrace my friend recorded, which reproduces the issue on his system when played back.

The stack my friend uses is (Debian Stretch with backports as a base):
GPU: Oland XT [R7 250] (ChipID = 0x6610)
Mesa: Git:master/8847370424
libdrm: 2.4.95-1~bpo9+1
LLVM: SVN:trunk/r350064 (8.0 devel)
X.Org: 2:1.19.2-1+deb9u5
Linux: 4.20-1~exp1
Firmware: 20180825+dfsg-1~bpo9+1
DDX: 1:7.8.0-1+b1

Let me know, if you need anything else.