I have installed the Fedora 28 XFCE spin, and am very impressed with the work you have done. I have one minor issue and I am only raising it because I am confused about what is happening and which drivers I should be using. This is a Sempron 3850 that uses [AMD/ATI] Kabini [Radeon HD 8280 / R3 Series] graphics. In Debian Buster, I just use the AMD ucode. What is happening is, I get the login window in lightdm, then when I put in my password, the screen goes blank, then I have to login to lightdm the 2nd time, then it works and I no longer see errors in dmesg. Here is the error I get:

[ 26.062943] showsignalmsg: 8 callbacks suppressed [ 27.683791] radeondpauxtransfernative: 74 callbacks suppressed [ 43.166719] radeondpauxtransfernative: 74 callbacks suppressed

Here is the output of lsmod

lsmod | grep radeon

radeon 1654784 3 i2calgobit 16384 2 amdgpu,radeon drmkmshelper 200704 2 amdgpu,radeon ttm 126976 2 amdgpu,radeon drm 454656 8 amdgpu,radeon,gpusched,ttm,drmkms_helper

And here is the part of the boot log where it appears to load the Kabini microcode, then also loads the radeon driver:

[    5.594069] [drm] radeon kernel modesetting enabled.
[    5.597263] checking generic (c0000000 300000) vs hw (c0000000 10000000)
[    5.597265] fb: switching to radeondrmfb from EFI VGA
[    5.600370] Console: switching to colour dummy device 80x25
[    5.601237] [drm] initializing kernel modesetting (KABINI 0x1002:0x9836 0x1458:0xD000 0x00).
[    5.601279] [drm] doorbell mmio base: 0xD0000000
[    5.601286] [drm] doorbell mmio size: 8388608
[    5.601375] ATOM BIOS: AMD
[    5.601460] radeon 0000:00:01.0: VRAM: 512M 0x0000000000000000 - 0x000000001FFFFFFF (512M used)
[    5.601473] radeon 0000:00:01.0: GTT: 2048M 0x0000000020000000 - 0x000000009FFFFFFF
[    5.601488] [drm] Detected VRAM RAM=512M, BAR=256M
[    5.601495] [drm] RAM width 128bits DDR
[    5.601633] [TTM] Zone  kernel: Available graphics memory: 3795232 kiB
[    5.601641] [TTM] Zone   dma32: Available graphics memory: 2097152 kiB
[    5.601648] [TTM] Initializing pool allocator
[    5.601664] [TTM] Initializing DMA pool allocator
[    5.601717] [drm] radeon: 512M of VRAM memory ready
[    5.601726] [drm] radeon: 2048M of GTT memory ready.
[    5.601752] [drm] Loading kabini Microcode
[    5.602121] [drm] Internal thermal controller without fan control
[    5.602793] [drm] radeon: dpm initialized
[    5.602989] [drm] Found UVD firmware Version: 1.64 Family ID: 9
[    5.606086] [drm] Found VCE firmware/feedback version 40.2.2 / 15!
[    5.606117] [drm] GART: num cpu pages 524288, num gpu pages 524288
[    5.633154] [drm] PCIE GART of 2048M enabled (table at 0x000000000030E000).
[    5.633457] radeon 0000:00:01.0: WB enabled
[    5.633505] radeon 0000:00:01.0: fence driver on ring 0 use gpu addr 0x0000000020000c00 and cpu addr 0x00000000fc907248
[    5.633519] radeon 0000:00:01.0: fence driver on ring 1 use gpu addr 0x0000000020000c04 and cpu addr 0x000000001ea94925
[    5.633531] radeon 0000:00:01.0: fence driver on ring 2 use gpu addr 0x0000000020000c08 ...