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Mendy Kevin
Mendy Kevin

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Connecting an External Ultrawide to Ubuntu — Lid Close, Resolution, and Scaling Fixes.

#linux #ubuntu #gnome #systemd

The Setup

HP EliteBook 745 G6 → USB-C → DisplayPort → 3440×1440 ultrawide monitor.

I wanted to close the lid and keep presenting on the external display. Ubuntu kept suspending. The monitor wasn't offering its native resolution. Here's everything I did, in order.

Step 1 — Connect and Check What's Detected 

xrandr --query | grep -E "connected|HDMI|DP|eDP"
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My output:

eDP connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 309mm x 174mm
DisplayPort-0 disconnected
DisplayPort-1 disconnected
DisplayPort-2 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 797mm x 334mm
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The external monitor is on DisplayPort-2 (USB-C alt mode). Good — DP has enough bandwidth for 3440×1440.

Step 2 — Check Available Resolutions 

xrandr --query | grep -A 20 "DisplayPort-2 connected"
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This showed 3440×1440 was not in the advertised modes list. The monitor's EDID wasn't exposing it, so the GUI had no option to select it.

Step 3 — Add the Missing Resolution (X11)

Generate the modeline:

cvt 3440 1440 60
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Output:

# 3440x1440 59.94 Hz (CVT) hsync: 89.48 kHz; pclk: 419.50 MHz
Modeline "3440x1440_60.00"  419.50  3440 3696 4064 4688  1440 1443 1453 1493 -hsync +vsync
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Add and apply:

xrandr --newmode "3440x1440_60.00"  419.50  3440 3696 4064 4688  1440 1443 1453 1493 -hsync +vsync
xrandr --addmode DisplayPort-2 3440x1440_60.00
xrandr --output DisplayPort-2 --mode 3440x1440_60.00
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If the screen goes black, wait 10 seconds then type:

xrandr --output DisplayPort-2 --mode 1920x1080

If the full-blanking modeline doesn't work, try reduced blanking (lower bandwidth):

cvt -r 3440 1440 60
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Then use that modeline in the same --newmode / --addmode / --mode sequence.

Make It Persist Across Reboots 

sudo nano /etc/X11/xorg.conf.d/34-monitor.conf
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Section "Monitor"
    Identifier "Ultrawide"
    Modeline "3440x1440_60.00"  419.50  3440 3696 4064 4688  1440 1443 1453 1493 -hsync +vsync
    Option "PreferredMode" "3440x1440_60.00"
EndSection
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Wayland users: xrandr won't work. Select "Ubuntu on Xorg" at the login screen, or use GNOME Settings which reads DRM modes directly.

Step 4 — Diagnose the Lid Close Issue

Close the lid. Reopen. Check what actually happened:

journalctl --since "2 min ago" | grep -iE "lid|suspend|sleep|logind"
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This confirmed the system was suspending.

Check for Inhibitors 

systemd-inhibit
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The critical line:

kmend  1000  kmend  8753  gsd-power  handle-lid-switch  External monitor attached or configuration changed recently  block
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This is the smoking gun. gsd-power is holding a block-mode inhibitor on handle-lid-switch. This means logind's HandleLidSwitch setting is completely bypassed — GNOME is in charge of the lid event, not logind.

Step 5 — Fix the Lid Close (GNOME Settings)

Since GNOME is in charge, you need to fix GNOME's lid settings, not logind's:

gsettings set org.gnome.settings-daemon.plugins.power lid-close-ac-action 'nothing'
gsettings set org.gnome.settings-daemon.plugins.power lid-close-battery-action 'nothing'
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Verify:

gsettings get org.gnome.settings-daemon.plugins.power lid-close-ac-action
gsettings get org.gnome.settings-daemon.plugins.power lid-close-battery-action
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Both should return 'nothing'. This takes effect immediately.

Common mistake: setting sleep-inactive-ac-type to 'nothing' does NOT affect the lid. That controls the idle timeout. The lid-specific keys are lid-close-ac-action and lid-close-battery-action.

Step 6 — Fix Logind (Defense in Depth)

Create a drop-in:

sudo mkdir -p /etc/systemd/logind.conf.d
sudo nano /etc/systemd/logind.conf.d/99-lid.conf
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[Login]
HandleLidSwitch=ignore
HandleLidSwitchExternalPower=ignore
HandleLidSwitchDocked=ignore
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The [Login] header is mandatory. Without it, the file is silently ignored.

Reload and verify:

sudo systemctl reload systemd-logind
busctl get-property org.freedesktop.login1 /org/freedesktop/login1 org.freedesktop.login1.Manager HandleLidSwitch
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Expected: s "ignore"

Step 7 — Mask Suspend Targets (Optional Nuclear Option) 

sudo systemctl mask suspend.target suspend-then-hibernate.target hibernate.target hybrid-sleep.target
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Undo later:

sudo systemctl unmask suspend.target suspend-then-hibernate.target hibernate.target hybrid-sleep.target
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Step 8 — Reboot and Verify 

sudo reboot
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After reboot, close the lid, reopen, then:

journalctl --since "2 min ago" | grep -iE "lid|suspend|sleep|logind"
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No suspend entries = you're good.

Step 9 — HP BIOS (If It Still Misbehaves)

Some HP EliteBooks have a firmware-level lid handler that fires before the OS. Reboot → F10 → Advanced → Power Management:

  • Lid Close Action → Do Nothing
  • Smart Standby → Disable

Quick Reference

Problem Root Cause Fix
Lid closes → suspend gsd-power holds block inhibitor; follows lid-close-*-action (defaults to suspend) gsettings set ... lid-close-ac-action 'nothing'
Lid closes → suspend (no external monitor) logind default is suspend Drop-in with HandleLidSwitch=ignore
3440×1440 not in GUI Monitor EDID doesn't advertise it xrandr --newmode + --addmode + --mode
3440×1440 not working on HDMI HDMI 1.4 bandwidth limit (~10.2 Gbps) Use USB-C → DisplayPort instead

The key insight: when an external monitor is attached, GNOME grabs the lid switch handler and ignores logind entirely. Most guides stop at editing logind.conf and wonder why it doesn't work. The actual fix is the gsettings command.

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