I moved over to Hyprland as my primary desktop environment several months ago after wrestling with some other Wayland desktop environments. It does plenty of things well and finally allowed me to do screen sharing during meetings without much hassle.

A couple of small utilities, hyperidle and hyprlock, handle idle time and locking the screen when I step away from my desk. However, I kept coming back after lunch and found that both of my displays were often unresponsive with a blank screen after unlocking.

Diagnosing the issue #

I ran into this issue when I’d come back from lunch, hit the spacebar, and both monitors remained in power save mode. The power lights on both monitors were blinking, indicating that they were still in a low-power state.

If I turned off each monitor and turned it back on, the displays would come back on about 80% of the time. Power cycling the displays was annoying and it became more annoying when I found that my workspaces had migrated between the monitors. Nothing was in the right place any longer! 😭

I finally got in a situation where one monitor powered up and the other was still off! Time to run some diagnostic commands!

Digging in #

You can list the monitors in hyprland with hyprctl monitors all. Narrow that down by specifically looking for the DPMS (Display Power Management Signaling) status with this command:

$ hyprctl monitors | grep -E "(Monitor|dpms|disabled)")

Monitor DP-1 (ID 0):
	dpmsStatus: 1
	disabled: false
Monitor DP-2 (ID 1):
	dpmsStatus: 1
	disabled: false

In my case, the DPMS status for both monitors was 1, which means both monitors are on. Neither monitor is disabled. However, the monitor connected to DP-1 was still blank!

Even ddcutil said the same thing:

$ ddcutil detect

Display 1                                          
   I2C bus:  /dev/i2c-9
   DRM_connector:           card1-DP-1
   EDID synopsis:
      Mfg id:               DEL - Dell Inc.
      Model:                DELL U2723QE
      Product code:         17016  (0x4278)
      Serial number:        85P0F34
      Binary serial number: 1128482124 (0x4343454c)
      Manufacture year:     2024,  Week: 38
   VCP version:         2.1

Display 2
   I2C bus:  /dev/i2c-10
   DRM_connector:           card1-DP-2
   EDID synopsis:
      Mfg id:               DEL - Dell Inc.
      Model:                DELL U2723QE
      Product code:         17016  (0x4278)
      Serial number:        55P0F34
      Binary serial number: 1128481356 (0x4343424c)
      Manufacture year:     2024,  Week: 38
   VCP version:         2.1

Then I wondered if I could just cycle the DPMS and bring them both back:

$ hyprctl dispatch dpms off; sleep 1; hyprctl dispatch dpms on

Both monitors turned on and displayed my desktop! But why?

Could it be amdgpu? #

Checking the system journal with journalctl revealed an interesting message:

kernel: amdgpu 0000:03:00.0: [drm] REG_WAIT timeout 1us * 100 tries - dcn32_program_compbuf_size line:139

This suggests there’s some kind of a drm timeout when the AMD GPU driver is trying to do something.

The Arch Linux wiki suggests that disabling AMD’s low power state, GFXOFF, might help with similar issues. You can set a kernel parameter such as amdgpu.ppfeaturemask=0xfffd7fff to disable it. I’ve had bad luck in the past with these amdgpu parameters, so I wanted a workaround for now until I could test it more.

A (sorta) elegant workaround #

Hyprland has a key binding system that allows you to execute certain key combinations even when the screen is locked. I was already using some of these key bindings so that I could adjust my music even with the screen locked¹:

> grep bindl ~/.config/hypr/hyprland.conf

bindl = , XF86AudioNext, exec, playerctl next
bindl = , XF86AudioPause, exec, playerctl play-pause
bindl = , XF86AudioPlay, exec, playerctl play-pause
bindl = , XF86AudioPrev, exec, playerctl previous

The normal key bindings in hyprland use bind, but bindl works even when the screen is locked. Here’s what I added:

> grep bindl ~/.config/hypr/hyprland.conf

bindl = , XF86AudioNext, exec, playerctl next
bindl = , XF86AudioPause, exec, playerctl play-pause
bindl = , XF86AudioPlay, exec, playerctl play-pause
bindl = , XF86AudioPrev, exec, playerctl previous
bindl = $mainMod SHIFT, D, exec, hyprctl dispatch dpms off && sleep 1 && hyprctl dispatch dpms on

Now I can hold down Mod + Shift + D when I return to my desk after lunch and both monitors come back on instantly!

I’ll let you know if I get around to messing with amdgpu.ppfeaturemask to see if that resolves the underlying issue. 🤓