Hi all, how's it going

? I've just installed
Peppermint 9 64-bit to this
HP 6930p Elitebook. It runs almost perfectly too. The problem I'm having, is severe screen flickering when the laptop lid is opened. The power management while plugged in, is set to
Switch off display when the lid is closed. I've tried disabling the
Desktop Effects. This makes no difference. I've tried using the
Mate Power Manager instead of the
XFCE4 Power Manager. That also made no difference.
Ctrl+Alt+F2 followed by,
Ctrl+Alt+F7 brings
X back to normal.
Previously, I had
Xubuntu 18.04 LTS installed. The identical flickering screen issues were present with this installation too. I just never got around to trouble shooting it. I swapped this machine to
Peppermint 9, simply because it's more refined and much quicker. Any help is much appreciated

. The machine's specs are below:
andy@andy-HP-EliteBook-6930p ~ $ inxi -Fz
System: Host: andy-HP-EliteBook-6930p Kernel: 4.15.0-38-generic x86_64 bits: 64
Desktop: N/A Distro: Peppermint Nine
Machine: Device: laptop System: Hewlett-Packard product: HP EliteBook 6930p v: F.16 serial: N/A
Mobo: Hewlett-Packard model: 30DB v: KBC Version 87.2A serial: N/A
BIOS: Hewlett-Packard v: 68PCU Ver. F.16 date: 12/08/2009
Battery BAT0: charge: 43.5 Wh 96.6% condition: 45.0/48.8 Wh (92%)
CPU: Dual core Intel Core2 Duo P8600 (-MCP-) cache: 3072 KB
clock speeds: max: 2401 MHz 1: 1276 MHz 2: 1456 MHz
Graphics: Card: Intel Mobile 4 Series Integrated Graphics Controller
Display Server: x11 (X.Org 1.19.6 )
drivers: modesetting (unloaded: fbdev,vesa)
Resolution: 1280x800@59.99hz
OpenGL: renderer: Mesa DRI Mobile Intel GM45 Express
version: 2.1 Mesa 18.0.5
Audio: Card Intel 82801I (ICH9 Family) HD Audio Controller driver: snd_hda_intel
Sound: Advanced Linux Sound Architecture v: k4.15.0-38-generic
Network: Card-1: Intel 82567LM Gigabit Network Connection driver: e1000e
IF: enp0s25 state: down mac: <filter>
Card-2: Intel Ultimate N WiFi Link 5300 driver: iwlwifi
IF: wls1 state: up mac: <filter>
Drives: HDD Total Size: 300.1GB (59.4% used)
ID-1: /dev/sda model: DREVO_X1 size: 60.0GB
ID-2: /dev/sdb model: SanDisk_SDSSDA24 size: 240.1GB
ID-3: /dev/mmcblk0 model: N/A size: 16.0GB
Partition: ID-1: / size: 20G used: 7.1G (38%) fs: ext4 dev: /dev/sda1
ID-2: /home size: 12G used: 1.2G (11%) fs: ext4 dev: /dev/sda2
RAID: No RAID devices: /proc/mdstat, md_mod kernel module present
Sensors: System Temperatures: cpu: 51.0C mobo: 24.9C
Fan Speeds (in rpm): cpu: N/A
Info: Processes: 205 Uptime: 12:22 Memory: 1504.9/3845.7MB
Client: Shell (bash) inxi: 2.3.56
andy@andy-HP-EliteBook-6930p ~ $