I am also having this problem, with a ThinkPad, Radeon 780M chipset, via HDMI port. When it goes to sleep, the laptop screen wakes up but the external monitor doesn’t. Today unplugging it and plugging it back in wakes up the monitor, but hasn’t always.
Welcome to 
Could you provide the output of inxi -Fzxx in </> preformatted text here:
If you can consistently reproduce the issue can you provide the output of :
journalctl | grep -i 'suspend\|resume'
inxi
System:
Kernel: 6.9.12-200.fc40.x86_64 arch: x86_64 bits: 64 compiler: gcc
v: 2.41-37.fc40
Desktop: GNOME v: 46.3.1 tk: GTK v: 3.24.43 wm: gnome-shell dm: GDM
Distro: Fedora Linux 40 (Workstation Edition)
Machine:
Type: Laptop System: LENOVO product: 21K5000TUS v: ThinkPad P14s Gen 4
serial: <superuser required> Chassis: type: 10 serial: <superuser required>
Mobo: LENOVO model: 21K5000TUS v: SDK0T76530 WIN
serial: <superuser required> part-nu: LENOVO_MT_21K5_BU_Think_FM_ThinkPad
P14s Gen 4 UEFI: LENOVO v: R2FET57W (1.37 ) date: 05/20/2024
Battery:
ID-1: BAT0 charge: 54.5 Wh (99.8%) condition: 54.6/52.5 Wh (104.0%)
volts: 17.7 min: 15.4 model: Celxpert 5B11M90028 serial: <filter>
status: full
CPU:
Info: 8-core model: AMD Ryzen 7 PRO 7840U w/ Radeon 780M Graphics bits: 64
type: MT MCP arch: Zen 4 rev: 1 cache: L1: 512 KiB L2: 8 MiB L3: 16 MiB
Speed (MHz): avg: 874 high: 2832 min/max: 400/5132 cores: 1: 400 2: 400
3: 400 4: 2832 5: 400 6: 1926 7: 2045 8: 400 9: 400 10: 400 11: 1397 12: 400
13: 400 14: 400 15: 400 16: 1397 bogomips: 105396
Flags: avx avx2 ht lm nx pae sse sse2 sse3 sse4_1 sse4_2 sse4a ssse3 svm
Graphics:
Device-1: AMD Phoenix1 vendor: Lenovo driver: amdgpu v: kernel arch: RDNA-3
pcie: speed: 16 GT/s lanes: 16 ports: active: HDMI-A-1,eDP-1 empty: DP-1,
DP-2, DP-3, DP-4, DP-5, DP-6, Writeback-1 bus-ID: 64:00.0
chip-ID: 1002:15bf temp: 40.0 C
Device-2: Chicony Integrated Camera driver: uvcvideo type: USB rev: 2.0
speed: 480 Mb/s lanes: 1 bus-ID: 3-1:2 chip-ID: 04f2:b7c0
Display: wayland server: X.org v: 1.20.14 with: Xwayland v: 24.1.1
compositor: gnome-shell driver: gpu: amdgpu display-ID: 0
Monitor-1: HDMI-A-1 model: HP Z27 res: 3840x2160 dpi: 163
diag: 685mm (27")
Monitor-2: eDP-1 model: Samsung 0x4193 res: 2880x1800 dpi: 242
diag: 356mm (14")
API: OpenGL v: 4.6 vendor: amd mesa v: 24.1.5 glx-v: 1.4 es-v: 3.2
direct-render: yes renderer: AMD Radeon 780M (radeonsi gfx1103_r1 LLVM
18.1.6 DRM 3.57 6.9.12-200.fc40.x86_64) device-ID: 1002:15bf
display-ID: :0.0
API: EGL Message: EGL data requires eglinfo. Check --recommends.
Audio:
Device-1: AMD Rembrandt Radeon High Definition Audio vendor: Lenovo
driver: snd_hda_intel v: kernel pcie: speed: 16 GT/s lanes: 16
bus-ID: 64:00.1 chip-ID: 1002:1640
Device-2: AMD ACP/ACP3X/ACP6x Audio Coprocessor vendor: Lenovo
driver: snd_pci_ps v: kernel pcie: speed: 16 GT/s lanes: 16 bus-ID: 64:00.5
chip-ID: 1022:15e2
Device-3: AMD Family 17h/19h HD Audio vendor: Lenovo driver: snd_hda_intel
v: kernel pcie: speed: 16 GT/s lanes: 16 bus-ID: 64:00.6 chip-ID: 1022:15e3
API: ALSA v: k6.9.12-200.fc40.x86_64 status: kernel-api
Server-1: JACK v: 1.9.22 status: off
Server-2: PipeWire v: 1.0.7 status: active with: 1: pipewire-pulse
status: active 2: wireplumber status: active 3: pipewire-alsa type: plugin
Network:
Device-1: Realtek RTL8111/8168/8211/8411 PCI Express Gigabit Ethernet
vendor: Lenovo driver: r8169 v: kernel pcie: speed: 2.5 GT/s lanes: 1
port: 6000 bus-ID: 01:00.0 chip-ID: 10ec:8168
IF: enp1s0f0 state: down mac: <filter>
Device-2: Qualcomm QCNFA765 Wireless Network Adapter vendor: Lenovo
driver: ath11k_pci v: kernel pcie: speed: 8 GT/s lanes: 1 bus-ID: 02:00.0
chip-ID: 17cb:1103
IF: wlp2s0 state: up mac: <filter>
Bluetooth:
Device-1: USI driver: btusb v: 0.8 type: USB rev: 1.1 speed: 12 Mb/s
lanes: 1 bus-ID: 1-3.1:5 chip-ID: 10ab:9309
Report: btmgmt ID: hci0 rfk-id: 1 state: up address: <filter> bt-v: 5.3
lmp-v: 12
Drives:
Local Storage: total: 953.87 GiB used: 251.17 GiB (26.3%)
ID-1: /dev/nvme0n1 vendor: SK Hynix model: HFS001TEJ9X162N
size: 953.87 GiB speed: 63.2 Gb/s lanes: 4 serial: <filter> temp: 41.9 C
Partition:
ID-1: / size: 952.27 GiB used: 250.76 GiB (26.3%) fs: btrfs dev: /dev/dm-0
mapped: luks-9d79c19d-5a04-4ccb-a2b3-7cbb350b0eb9
ID-2: /boot size: 973.4 MiB used: 405.9 MiB (41.7%) fs: ext4
dev: /dev/nvme0n1p2
ID-3: /boot/efi size: 598.8 MiB used: 19.1 MiB (3.2%) fs: vfat
dev: /dev/nvme0n1p1
ID-4: /home size: 952.27 GiB used: 250.76 GiB (26.3%) fs: btrfs
dev: /dev/dm-0 mapped: luks-9d79c19d-5a04-4ccb-a2b3-7cbb350b0eb9
Swap:
ID-1: swap-1 type: zram size: 8 GiB used: 0 KiB (0.0%) priority: 100
dev: /dev/zram0
Sensors:
System Temperatures: cpu: 43.0 C mobo: N/A
Fan Speeds (rpm): fan-1: 0 fan-2: 0
Info:
Memory: total: 60 GiB available: 58.5 GiB used: 6.37 GiB (10.9%)
Processes: 471 Power: uptime: 4h 49m wakeups: 2 Init: systemd v: 255
target: graphical (5) default: graphical
Packages: pm: flatpak pkgs: 10 Compilers: gcc: 14.2.1 Shell: Bash
v: 5.2.26 running-in: gnome-terminal inxi: 3.3.34
Could you please try an older kernel version? You should have 3 available.
If you do not know how to do this, Here is a quick guide
Since you should have Grub, refer to that section. Report back if the issue persists.
This issue seemed to go away with future kernel versions.
for me, it got much better, but did not go away. Now it happens maybe 1/100 times. Still very annoying when it does, I have to power off my pc and reboot, loosing anything unsaved. But not near the problem it was.
I had this on Windows with a HD 7850 years ago; I think I resolved it by forcing always-3D clocks, implying it could be a low-power-state that’s causing the monitor not to reinitialize.
Reading the linked report reminded me of VRAM also being odd on that GPU (it fluctuating and causing multi-monitor issues), which I recall being distinctly linked to other issues.
Something like this should force high-perf clocks and serve as a quick-test:
echo 'manual' | sudo tee '/sys/class/drm/card'*'/device/power_dpm_force_performance_level'
echo '1' | sudo tee '/sys/class/drm/card'*'/device/pp_power_profile_mode'
I used that to workaround https://gitlab.freedesktop.org/drm/amd/-/issues/1500