Comment 48 for bug 1715749

I'm having the same issue on Mint 19.3.

Just installed mint a couple days ago.

Laptop is docked with 1 external monitor attached. The laptop screen goes black for a few seconds at a time. External monitor stays active, and I can use the external monitor as usual during the blackout. The black laptop screen come back to life on its own, and all is back to normal.

Happens every few hours.

Here's inxi:

$ inxi -Fxz
System: Host: hp840 Kernel: 5.3.0-42-generic x86_64 bits: 64 compiler: gcc v: 7.4.0 Desktop: Cinnamon 4.4.8
           Distro: Linux Mint 19.3 Tricia base: Ubuntu 18.04 bionic
Machine: Type: Laptop System: Hewlett-Packard product: HP EliteBook 840 G1 v: A3009DD10303 serial: <filter>
           Mobo: Hewlett-Packard model: 198F v: KBC Version 15.59 serial: <filter> BIOS: Hewlett-Packard v: L71 Ver. 01.44
           date: 04/12/2018
Battery: ID-1: BAT0 charge: 40.9 Wh condition: 41.2/41.2 Wh (100%) model: Hewlett-Packard Primary status: Unknown
CPU: Topology: Dual Core model: Intel Core i7-4600U bits: 64 type: MT MCP arch: Haswell rev: 1 L2 cache: 4096 KiB
           flags: lm nx pae sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx bogomips: 21550
           Speed: 898 MHz min/max: 800/3300 MHz Core speeds (MHz): 1: 2252 2: 2779 3: 1354 4: 2266
Graphics: Device-1: Intel Haswell-ULT Integrated Graphics vendor: Hewlett-Packard driver: i915 v: kernel bus ID: 00:02.0
           Display: x11 server: X.Org 1.20.5 driver: modesetting unloaded: fbdev,vesa
           resolution: 1600x900~60Hz, 1920x1080~60Hz
           OpenGL: renderer: Mesa DRI Intel Haswell Mobile v: 4.5 Mesa 19.2.8 direct render: Yes
Audio: Device-1: Intel Haswell-ULT HD Audio vendor: Hewlett-Packard driver: snd_hda_intel v: kernel bus ID: 00:03.0
           Device-2: Intel 8 Series HD Audio vendor: Hewlett-Packard driver: snd_hda_intel v: kernel bus ID: 00:1b.0
           Device-3: Audio-Technica type: USB driver: hid-generic,snd-usb-audio,usbhid bus ID: 2-1.2.4.4:11
           Sound Server: ALSA v: k5.3.0-42-generic
Network: Device-1: Intel Ethernet I218-LM vendor: Hewlett-Packard driver: e1000e v: 3.2.6-k port: 3080 bus ID: 00:19.0
           IF: enp0s25 state: up speed: 1000 Mbps duplex: full mac: <filter>
           Device-2: Intel Wireless 7260 driver: iwlwifi v: kernel port: ef80 bus ID: 02:00.0
           IF: wlo1 state: down mac: <filter>
Drives: Local Storage: total: 223.57 GiB used: 91.40 GiB (40.9%)
           ID-1: /dev/sda vendor: Intel model: SSDSC2BF240A4H size: 223.57 GiB
Partition: ID-1: / size: 219.06 GiB used: 91.40 GiB (41.7%) fs: ext4 dev: /dev/sda1
Sensors: System Temperatures: cpu: 43.0 C mobo: N/A
           Fan Speeds (RPM): N/A
Info: Processes: 226 Uptime: 52m Memory: 15.54 GiB used: 2.85 GiB (18.3%) Init: systemd runlevel: 5 Compilers: gcc: 7.5.0
           Shell: bash v: 4.4.20 inxi: 3.0.32