"LightDM failed to start" on Ryzen Pro

I’m installing Manjaro i3 on a new ThinkPad T14 with an AMD 4750U processor (and thus it’s graphics as well).

I get an error from systemd on start up saying [FAILED] Failed to start Light Display Manager. Going into tty2 (Ctrl + Alt + F2) and running systemctl status lightdm.service I get:

lightdm.service - Light Display Manager
Loaded: loaded (/usr/lib/systemd/system/lightdm.service; enabled; vendor preset: disabled)
Active: failed (Result: exit-code) since Mon 2021-05-10 01:04:46 EDT 37s ago
Docs: man:lightdm(1)
Process: 775 ExecStart=/usr/bin/lightdm (code=exited, status=1/FAILURE)
Main PID: 775 (code=exited, status=1/FAILURE)

May 10 04:04:46 systemd[1]: lightdm.service: Scheduled restart job, restart counter is at 5.
May 10 04:04:46 systemd[1]: Stopped Light Display Manager.
May 10 04:04:46 systemd[1]: lightdm.service: Start request repeated too quickly.
May 10 04:04:46 systemd[1]: lightdm.service: Failed with result ‘exit-code’.
May 10 04:04:46 systemd[1]: Failed to start Light Display Manager.

However, in said tty2, running:

systemctl enable lightdm.service
systemctl start lightdm.service

starts up lightDM just fine.

I’ve followed a few similar threads on the forum, but I don’t think I’ve found one like this. While I do technically have a workaround, I’d rather not have to go into tty2 to start up lightdm (plus I’m guessing that systemd isn’t loading the rest of the system as a result of this early failure).


Adding the instruction mentioned in this ArchWiki page fixed the issue:


Found via this arch forum post, where the error messages shown in /var/log/lightdm/lightdm.log match practically identically to that reported in the post there.

1 Like

can you provide

inxi -Fza
❯ inxi -Fza
System:    Kernel: 5.10.34-1-MANJARO x86_64 bits: 64 compiler: gcc v: 10.2.0 
           parameters: BOOT_IMAGE=/boot/vmlinuz-5.10-x86_64 root=UUID=cec2d4e0-d852-4f58-a084-9d86bcb73abe rw 
           apparmor=1 security=apparmor udev.log_priority=3 quiet apparmor=1 security=apparmor udev.log_priority=3 
           resume=/dev/disk/by-uuid/cec2d4e0-d852-4f58-a084-9d86bcb73abe resume_offset=40210432 
           Desktop: i3 4.19.1 info: polybar vt: 7 dm: LightDM 1.30.0 Distro: Manjaro Linux base: Arch Linux 
Machine:   Type: Laptop System: LENOVO product: 20UECTO1WW v: ThinkPad T14 Gen 1 serial: <filter> Chassis: 
           type: 10 serial: <filter> 
           Mobo: LENOVO model: 20UECTO1WW serial: <filter> UEFI: LENOVO v: R1BET61W(1.30 ) date: 12/21/2020 
Battery:   ID-1: BAT0 charge: 36.7 Wh (69.5%) condition: 52.8/50.5 Wh (104.6%) volts: 12.0 min: 11.5 
           model: SMP 5B10W139 type: Li-poly serial: <filter> status: Discharging cycles: 2 
CPU:       Info: 8-Core model: AMD Ryzen 7 PRO 4750U with Radeon Graphics bits: 64 type: MT MCP arch: Zen 2 
           family: 17 (23) model-id: 60 (96) stepping: 1 microcode: 8600106 cache: L2: 4 MiB 
           flags: avx avx2 lm nx pae sse sse2 sse3 sse4_1 sse4_2 sse4a ssse3 svm bogomips: 54295 
           Speed: 1397 MHz min/max: 1400/1700 MHz boost: enabled Core speeds (MHz): 1: 1397 2: 1397 3: 1397 
           4: 1397 5: 1397 6: 1397 7: 1397 8: 1396 9: 1397 10: 1397 11: 1397 12: 1396 13: 1395 14: 1397 15: 1397 
           16: 1396 
           Vulnerabilities: Type: itlb_multihit status: Not affected 
           Type: l1tf status: Not affected 
           Type: mds status: Not affected 
           Type: meltdown status: Not affected 
           Type: spec_store_bypass mitigation: Speculative Store Bypass disabled via prctl and seccomp 
           Type: spectre_v1 mitigation: usercopy/swapgs barriers and __user pointer sanitization 
           Type: spectre_v2 
           mitigation: Full AMD retpoline, IBPB: conditional, IBRS_FW, STIBP: conditional, RSB filling 
           Type: srbds status: Not affected 
           Type: tsx_async_abort status: Not affected 
Graphics:  Device-1: Advanced Micro Devices [AMD/ATI] Renoir vendor: Lenovo driver: amdgpu v: kernel 
           bus-ID: 07:00.0 chip-ID: 1002:1636 class-ID: 0300 
           Device-2: Chicony Integrated Camera type: USB driver: uvcvideo bus-ID: 2-2:2 chip-ID: 04f2:b6d0 
           class-ID: fe01 serial: <filter> 
           Display: x11 server: X.Org 1.20.11 compositor: picom v: git-dac85 driver: loaded: amdgpu,ati 
           unloaded: modesetting alternate: fbdev,vesa display-ID: :0 screens: 1 
           Screen-1: 0 s-res: 1920x1080 s-dpi: 96 s-size: 508x285mm (20.0x11.2") s-diag: 582mm (22.9") 
           Monitor-1: eDP res: 1920x1080 hz: 60 dpi: 158 size: 309x174mm (12.2x6.9") diag: 355mm (14") 
           OpenGL: renderer: AMD RENOIR (DRM 3.40.0 5.10.34-1-MANJARO LLVM 11.1.0) v: 4.6 Mesa 21.0.3 
           direct render: Yes 
Audio:     Device-1: Advanced Micro Devices [AMD/ATI] vendor: Lenovo driver: snd_hda_intel v: kernel 
           bus-ID: 07:00.1 chip-ID: 1002:1637 class-ID: 0403 
           Device-2: Advanced Micro Devices [AMD] Raven/Raven2/FireFlight/Renoir Audio Processor vendor: Lenovo 
           driver: snd_rn_pci_acp3x v: kernel alternate: snd_pci_acp3x bus-ID: 07:00.5 chip-ID: 1022:15e2 
           class-ID: 0480 
           Device-3: Advanced Micro Devices [AMD] Family 17h HD Audio vendor: Lenovo driver: snd_hda_intel 
           v: kernel bus-ID: 07:00.6 chip-ID: 1022:15e3 class-ID: 0403 
           Sound Server-1: ALSA v: k5.10.34-1-MANJARO running: yes 
           Sound Server-2: JACK v: 0.125.0 running: no 
           Sound Server-3: PulseAudio v: 14.2 running: yes 
Network:   Device-1: Realtek RTL8111/8168/8411 PCI Express Gigabit Ethernet vendor: Lenovo driver: r8169 v: kernel 
           port: 3400 bus-ID: 02:00.0 chip-ID: 10ec:8168 class-ID: 0200 
           IF: enp2s0f0 state: down mac: <filter> 
           Device-2: Intel Wi-Fi 6 AX200 driver: iwlwifi v: kernel port: 3000 bus-ID: 03:00.0 chip-ID: 8086:2723 
           class-ID: 0280 
           IF: wlp3s0 state: up mac: <filter> 
           Device-3: Realtek RTL8111/8168/8411 PCI Express Gigabit Ethernet vendor: Lenovo driver: r8169 v: kernel 
           port: 2000 bus-ID: 05:00.0 chip-ID: 10ec:8168 class-ID: 0200 
           IF: enp5s0 state: down mac: <filter> 
Bluetooth: Device-1: Intel AX200 Bluetooth type: USB driver: btusb v: 0.8 bus-ID: 6-4:3 chip-ID: 8087:0029 
           class-ID: e001 
           Report: rfkill ID: hci0 rfk-id: 2 state: up address: see --recommends 
Drives:    Local Storage: total: 931.51 GiB used: 46.58 GiB (5.0%) 
           SMART Message: Required tool smartctl not installed. Check --recommends 
           ID-1: /dev/nvme0n1 maj-min: 259:0 vendor: Samsung model: SSD 980 1TB size: 931.51 GiB block-size: 
           physical: 512 B logical: 512 B speed: 31.6 Gb/s lanes: 4 rotation: SSD serial: <filter> rev: 1B4QFXO7 
           temp: 34.9 C scheme: GPT 
Partition: ID-1: / raw-size: 931.22 GiB size: 915.53 GiB (98.32%) used: 46.58 GiB (5.1%) fs: ext4 
           dev: /dev/nvme0n1p2 maj-min: 259:2 
           ID-2: /boot/efi raw-size: 300 MiB size: 299.4 MiB (99.80%) used: 296 KiB (0.1%) fs: vfat 
           dev: /dev/nvme0n1p1 maj-min: 259:1 
Swap:      Kernel: swappiness: 60 (default) cache-pressure: 100 (default) 
           ID-1: swap-1 type: file size: 32 GiB used: 0 KiB (0.0%) priority: -2 file: /swapfile 
Sensors:   System Temperatures: cpu: 40.9 C mobo: 0.0 C gpu: amdgpu temp: 40.0 C 
           Fan Speeds (RPM): cpu: 0 
Info:      Processes: 301 Uptime: 12m wakeups: 1 Memory: 30.66 GiB used: 1.9 GiB (6.2%) Init: systemd v: 247 
           tool: systemctl Compilers: gcc: 10.2.0 Packages: pacman: 1232 lib: 307 Shell: Zsh v: 5.8 
           running-in: xfce4-terminal inxi: 3.3.04 

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