Starting from kernel 4.20.5, the plymouth bootup screen, as well as the textual framebuffer is garbled (see https://bugzilla.redhat.com/show_bug.cgi?id=1674065 for attachments), and the wayland graphical login never starts up. Instead, the monitor goes into power save (no video signal). There is no recovery from this state, and I have to power cycle the computer. All is fine on kernel-4.20.4, albeit that I have to disable amdgpu dc (options amdgpu dc=0), because it causes screen flicker. It appears dc was enabled by default since kernel 4.20, whereas it was disabled by default before that. Suspicious dmesg output: feb 08 22:50:34 kernel: [drm:atom_op_jump [amdgpu]] *ERROR* atombios stuck in loop for more than 5secs aborting feb 08 22:50:34 kernel: [drm:amdgpu_atom_execute_table_locked [amdgpu]] *ERROR* atombios stuck executing D6A0 (len 978, WS 0, PS 0) @ 0xD7EF feb 08 22:50:34 kernel: [drm:amdgpu_atom_execute_table_locked [amdgpu]] *ERROR* atombios stuck executing D55A (len 326, WS 0, PS 0) @ 0xD5F6 Hardware: - AMD Ryzen 1600X CPU - Asus B350M-A PRIME motherboard, BIOS version 4207 - MSI Radeon RX 560 AERO ITX 4G OC graphics card - Philips 276E8VJSB (4K) monitor Software: - Fedora 28 x86_64
Please attach the corresponding full output of dmesg. Can you bisect between 4.20.4 and 4.20.5?
Created attachment 281333 [details] journalctl --no-hostname -k for kernel-4.20.4-100.fc28.x86_64
Created attachment 281335 [details] journalctl --no-hostname -k for kernel-4.20.5-100.fc28.x86_64
The attached output from 4.20.4 shows DC being enabled. Does the problem really not happen with 4.20.4 and DC disabled?
Created attachment 281337 [details] Active kernel module parameters for 4.20.4 Hmm, I have: options amdgpu dc=0 in /etc/modprobe.d/amdgpu.conf, but my active module parameters say DC is enabled anyway...
Created attachment 281339 [details] journalctl --no-hostname -k for kernel-4.20.8-100.fc28.x86_64 with amdgpu.dc=1 Just found out changing stuff in /etc/modprobe.d/ has no effect until the next run of dracut :$ It turns out I can no longer use amdgpu without DC=1. With that enabled, the newer kernel run as normal. What probably happened is that I saw the flicker once, which is mentioned here: https://wiki.archlinux.org/index.php/AMDGPU : "If you experience flickering add amdgpu.dc=0 to your kernel parameters." That's when trouble began.