Black screen when amdgpu started during 6.2-rc1 boot
Brief summary of the problem:
I booted the Fedora Rawhide KDE Plasma live image Fedora-KDE-Live-x86_64-Rawhide-20221227.n.0.iso https://koji.fedoraproject.org/koji/buildinfo?buildID=2104562 from a USB flash drive written with Fedora Media Writer on an hp laptop with an integrated Radeon R5 GPU. The system froze with a black screen when amdgpu started during 6.2-rc1 kernel boot. When I booted with quiet rhgb removed from the kernel command line the last line shown before the black screen was kernel: [drm] amdgpu kernel modesetting enabled.
This problem happened each of several boots when using the amdgpu driver (the default). This problem didn't happen when I booted the same image using Troubleshooting > Boot Fedora-KDE-Plasma-live in basic graphics mode which used the simpledrm driver and started Plasma on X normally. This problem also didn't happen when I booted the image in a QEMU/KVM VM in GNOME Boxes with 3 GB RAM using the virtio-gpu driver.
The data from the previous boots using live images aren't saved by default so I couldn't get the journal that way as far as I knew. I installed kernel-6.2.0-0.rc1.14.fc38 in my Fedora 37 KDE Plasma installation and reproduced the problem 3 times with quiet rhgb removed from the kernel command line and sysrq_always_enabled drm.debug=14 added to it. I used sysrq+alt+r,s,u,b which rebooted the system so the kernel wasn't completely frozen. The journals from the boots with the problem weren't shown in journalctl. I booted with amdgpu.dc=0 on the kernel command line and the screen froze with the last line kernel: [drm] amdgpu kernel modesetting enabled. and the black screen didn't happen. I booted with drm.debug=94 on the kernel command line and the screen's drm settings were shown repeatedly until I rebooted after 2-3 minutes.
This problem didn't happen with kernel-6.1.0-65.fc38 or earlier in the Fedora Rawhide live image Fedora-KDE-Live-x86_64-Rawhide-20221217.n.0.iso. The problem was likely introduced in the 6.2 merge window. I haven't tried any of the 6.2 merge window kernels, but I might try to narrow down the problem using the Fedora Rawhide 6.2 merge window builds and then bisect using the narrowed range.
- CPU: AMD A10-9620P
- GPU: integrated AMD Radeon R5
- 00:01.0 VGA compatible controller : Advanced Micro Devices, Inc. [AMD/ATI] Wani [Radeon R5/R6/R7 Graphics] [1002:9874] (rev ca)
- System Memory: 8 GB
- Display(s): internal Elan touchscreen
- Type of Display Connection: eDP
- Distro name and Version: Fedora Rawhide/38
- Kernel version: 6.2.0-0.rc1.14.fc38
- Custom kernel: N/A
- AMD official driver version: N/A
How to reproduce the issue:
- Download Fedora Rawhide KDE Plasma live image Fedora-KDE-Live-x86_64-Rawhide-20221227.n.0.iso from https://koji.fedoraproject.org/koji/buildinfo?buildID=2104562
- Install Fedora Media Writer if isn't already with sudo dnf install mediawriter in Fedora
- Start Fedora Media Writer
- Write Fedora-KDE-Live-x86_64-Rawhide-20221227.n.0.iso to a USB flash drive in Fedora Media Writer
- Boot Fedora-KDE-Live-x86_64-Rawhide-20221227.n.0.iso from the USB flash drive with the default boot option using the amdgpu driver on a laptop with an integrated AMD Radeon R5 GPU