xrandr not listing all connected monitors

I tried to get my external screen on zoom level 100% while my laptop screen needed to stay on 200%. I must have done something wrong, because now only my external screen is working.

xrandr -q
Screen 0: minimum 8 x 8, current 6400 x 2160, maximum 32767 x 32767
DP-0 connected 2560x1440+3840+29 (normal left inverted right x axis y axis) 597mm x 336mm panning 2560x2160+3840+0 tracking 6400x2160+0+0 border 0/0/0/0 2560x1440 59.95*+ 2048x1152 60.00 1920x1200 59.88 1920x1080 60.00 59.94 50.00 29.97 25.00 23.98 1680x1050 59.95 1600x1200 60.00 1280x1024 75.02 60.02 1280x720 60.00 59.94 50.00 1200x960 59.90 1152x864 75.00 1024x768 75.03 60.00 800x600 75.00 60.32 720x576 50.00 720x480 59.94 640x480 75.00 59.94 59.93
DP-1 disconnected (normal left inverted right x axis y axis)
HDMI-0 disconnected (normal left inverted right x axis y axis)
DP-2 connected primary (normal left inverted right x axis y axis) 3840x2160 60.02 +
DP-3 disconnected (normal left inverted right x axis y axis)
DP-4 disconnected (normal left inverted right x axis y axis)

The DP-2 is my lap-top screen. When I try to set my laptop screen to auto, I get an error:

xrandr --output DP-2 --auto
xrandr: Configure crtc 1 failed
X Error of failed request: BadValue (integer parameter out of range for operation) Major opcode of failed request: 140 (RANDR) Minor opcode of failed request: 21 (RRSetCrtcConfig) Value in failed request: 0x0 Serial number of failed request: 47 Current serial number in output stream: 47

Listing the monitors only shows my external screen:

xrandr --listmonitors
Monitors: 1 0: +DP-0 2560/597x2131/336+3840+29 DP-0

I would be happy if I got things back to normal. Please keep in mind that I am not very experienced with Linux.

Running on: Ubuntu 18.04.3 LTS

dmesg output:

dmesg|grep -i "error\|warn\|fail"
[ 0.751166] RAS: Correctable Errors collector initialized.
[ 2.882702] EXT4-fs (nvme0n1p5): re-mounted. Opts: errors=remount-ro
[ 2.995387] ucsi_ccg 0-0008: i2c_transfer failed -6
[ 2.995401] ucsi_ccg 0-0008: ucsi_ccg_init failed - -6
[ 3.024793] iwlwifi 0000:70:00.0: Direct firmware load for iwlwifi-cc-a0-48.ucode failed with error -2
[ 3.024833] iwlwifi 0000:70:00.0: Direct firmware load for iwlwifi-cc-a0-47.ucode failed with error -2
[ 3.103590] nvidia: module verification failed: signature and/or required key missing - tainting kernel
[ 3.307996] thermal thermal_zone2: failed to read out thermal zone (-61)
[ 3.341566] ACPI Warning: \_SB.PCI0.PEG0.PEGP._DSM: Argument #4 type mismatch - Found [Buffer], ACPI requires [Package] (20190509/nsarguments-59)
[ 26.070764] pci 0000:02:00.0: BAR 13: failed to assign [io size 0x4000]
[ 26.070765] pci 0000:02:00.0: BAR 13: failed to assign [io size 0x4000]
[ 26.070773] pci 0000:03:00.0: BAR 13: failed to assign [io size 0x1000]
[ 26.070774] pci 0000:03:01.0: BAR 13: failed to assign [io size 0x1000]
[ 26.070775] pci 0000:03:02.0: BAR 13: failed to assign [io size 0x1000]
[ 26.070776] pci 0000:03:04.0: BAR 13: failed to assign [io size 0x1000]
[ 26.070778] pci 0000:03:00.0: BAR 13: failed to assign [io size 0x1000]
[ 26.070779] pci 0000:03:01.0: BAR 13: failed to assign [io size 0x1000]
[ 26.070780] pci 0000:03:02.0: BAR 13: failed to assign [io size 0x1000]
[ 26.070781] pci 0000:03:04.0: BAR 13: failed to assign [io size 0x1000]
[ 46.689443] xhci_hcd 0000:39:00.0: WARN: xHC restore state timeout
[ 46.689446] xhci_hcd 0000:39:00.0: PCI post-resume error -110!
[ 46.690250] xhci_hcd 0000:39:00.0: Host halt failed, -19
[ 46.690254] xhci_hcd 0000:39:00.0: Host not accessible, reset failed.
[ 105.772392] xhci_hcd 0000:39:00.0: WARN: xHC restore state timeout
[ 105.772393] xhci_hcd 0000:39:00.0: PCI post-resume error -110!
[ 105.772721] xhci_hcd 0000:39:00.0: Host halt failed, -19
[ 105.772722] xhci_hcd 0000:39:00.0: Host not accessible, reset failed.
[ 4572.630479] thermal thermal_zone2: failed to read out thermal zone (-61)

1 Answer

What solved it for me:

locate monitors.xml
/home/username/.config/monitors.xml
rm /home/username/.config/monitors.xml

And than go to Settings -> Screen Display -> Join Displays -> Apply

No my both monitors are back in business again.