I am using KDE neon User Edition (based on Ubuntu 18.04) and mesa 19.0.1 and so far it works without a problem on kernel 4.18.0, but when I upgraded to kernel 5.0.6 it got stuck at boot on "fb0: switching to amdgpudrmfb from VESA VGA"
When I dmesg|grep amdgpu on linux kernel 4.18.0-17-generic I get:
[ 1.727244] [drm] amdgpu kernel modesetting enabled.
[ 1.736425] fb: switching to amdgpudrmfb from VESA VGA
[ 1.737038] amdgpu 0000:02:00.0: Invalid PCI ROM header signature: expecting 0xaa55, got 0xffff
[ 1.737130] amdgpu 0000:02:00.0: VRAM: 4096M 0x000000F400000000 - 0x000000F4FFFFFFFF (4096M used)
[ 1.737132] amdgpu 0000:02:00.0: GTT: 256M 0x0000000000000000 - 0x000000000FFFFFFF
[ 1.737644] [drm] amdgpu: 4096M of VRAM memory ready
[ 1.737645] [drm] amdgpu: 4096M of GTT memory ready.
[ 1.983295] fbcon: amdgpudrmfb (fb0) is primary device
[ 1.983453] amdgpu 0000:02:00.0: fb0: amdgpudrmfb frame buffer device
[ 1.999387] [drm] Initialized amdgpu 3.26.0 20150101 for 0000:02:00.0 on minor 0
