Hi, I've been debugging a boot issue on my machine for a few days and wanted to bring it upstream since it's been sitting unassigned on Launchpad since February.
Hardware: AMD Picasso/Raven2 [1002:15d8], ASUS Vivo AIO V241DAP Kernel: 6.17.0-14-generic, Ubuntu 24.04 Problem: simpledrm registers on minor 0 at early boot: [0.404994] [drm] Initialized simpledrm 1.0.0 for simple-framebuffer.0 on minor 0 amdgpu loads ~16 seconds later and gets minor 1 since minor 0 is taken: [16.512693] [drm] Initialized amdgpu 3.64.0 for 0000:04:00.0 on minor 1 GDM starts, Mutter picks up card0 (simpledrm), calls drmModeAddFB, gets ENODEV and crashes: gnome-shell[1743]: Added device '/dev/dri/card0' (simpledrm) using atomic mode setting. gnome-shell[1743]: Integrated GPU /dev/dri/card0 selected as primary gnome-shell[1743]: Failed to ensure KMS FB ID on /dev/dri/card0: drmModeAddFB failed: No such device systemd restarts GDM. Second attempt finds card1 (amdgpu) and works: gnome-shell[2509]: Added device '/dev/dri/card1' (amdgpu) using atomic mode setting. gnome-shell[2509]: GPU /dev/dri/card1 selected primary from builtin panel presence This crash-restart cycle is the black screen on every boot. Workaround: Adding this to kernel cmdline fixes it: initcall_blacklist=simpledrm_platform_driver_init With simpledrm blocked, amdgpu claims card0 directly and GDM starts cleanly. Is a handoff from simpledrm to amdgpu expected to happen on this hardware? I couldn't find any takeover messages in dmesg. Full logs and investigation: https://github.com/jillravaliya/amdgpu-simpledrm-handoff-bug Launchpad: https://bugs.launchpad.net/ubuntu/+bug/2142087 Thanks Jill Ravaliya
