Mint boots into a black screen, but it boots normally

[mizuhoid]

My laptop boots into a black screen but the system itself boots normally.
I can hear the sound of volume up/down hotkey and can use an external display.
In live USB boot, laptop display works fine.

# Symptom
Black screen on both X and virtual consoles. I tested KDE and Xfce but neither worked.
When I connect an external display, I can see X and virtual consoles on the external display but not on the laptop.
When I disable & enable the laptop display via System Settings(KDE) -> Display and Monitor -> Display: checkbox, laptop display shows the KDE Desktop but after changing to a virtual console, nothing is shown and then backing to the KDE Desktop, the display gets black again.

Very rarely, the laptop screen shows both X and virtual consoles, changing virtual consoles and X works fine but I don't know the reason why...

# nomodeset
nomodeset works and I got a low resolution but working laptop display.

# Question
Generally, what should I do first to find the problem?

Code: Select all

$ inxi -Fxz

System:    Host: usb Kernel: 4.10.0-38-generic x86_64 (64 bit gcc: 5.4.0) Desktop: KDE Plasma 5 (Qt 5.6.1)
           Distro: Linux Mint 18.3 Sylvia
Machine:   System: HP (portable) product: HP ENVY x2 Detachable 12-g0xx
           Mobo: HP model: 845C v: 66.25 Bios: AMI v: F.05 date: 02/23/2018
CPU:       Dual core Intel Core i5-7Y54 (-HT-MCP-) cache: 4096 KB
           flags: (lm nx sse sse2 sse3 sse4_1 sse4_2 ssse3 vmx) bmips: 6432
           clock speeds: max: 3200 MHz 1: 500 MHz 2: 505 MHz 3: 517 MHz 4: 547 MHz
Graphics:  Card: Intel Device 591e bus-ID: 00:02.0
           Display Server: X.Org 1.18.4 drivers: intel (unloaded: fbdev,vesa)
           Resolution: 1280x1024@60.02hz, 1280x1024@60.02hz
           GLX Renderer: Mesa DRI Intel HD Graphics 615 (Kabylake GT2)
           GLX Version: 3.0 Mesa 17.0.7 Direct Rendering: Yes
Audio:     Card Intel Device 9d71 driver: snd_hda_intel bus-ID: 00:1f.3 Sound: ALSA v: k4.10.0-38-generic
Network:   Card: Intel Device 24fd driver: iwlwifi bus-ID: 02:00.0
           IF: wlo1 state: up speed: N/A duplex: N/A mac: <filter>
Drives:    HDD Total Size: 16.0GB (45.9% used) ID-1: /dev/nvme0n1 model: N/A size: 256.1GB
           ID-2: USB /dev/sdb model: Patriot_Memory size: 16.0GB
Partition: ID-1: / size: 15G used: 6.8G (50%) fs: ext4 dev: /dev/sdb1
RAID:      No RAID devices: /proc/mdstat, md_mod kernel module present
Sensors:   System Temperatures: cpu: 41.5C mobo: N/A
           Fan Speeds (in rpm): cpu: N/A
Info:      Processes: 197 Uptime: 16 min Memory: 632.2/7861.2MB Init: systemd runlevel: 5 Gcc sys: 5.4.0

Code: Select all

$ xrandr 
Screen 0: minimum 8 x 8, current 2560 x 1024, maximum 32767 x 32767
eDP1 connected primary 1280x1024+1280+0 (normal left inverted right x axis y axis) 259mm x 173mm
   1920x1280     60.00 +  48.01  
   1920x1200     59.95  
   1920x1080     59.93  
   1600x1200     60.00  
   1680x1050     59.95    59.88  
   1600x1024     60.17  
   1400x1050     59.98  
   1280x1024     60.02* 
   1440x900      59.89  
   1280x960      60.00  
   1360x768      59.80    59.96  
   1152x864      60.00  
   1024x768      60.00  
   960x640       60.00  
   800x600       60.32    56.25  
   640x480       59.94  
DP1 disconnected (normal left inverted right x axis y axis)
DP2 connected 1280x1024+0+0 (normal left inverted right x axis y axis) 337mm x 270mm
   1280x1024     60.02* 
   1024x768      60.00  
   800x600       60.32  
   640x480       59.94  
   720x400       70.08  
VIRTUAL1 disconnected (normal left inverted right x axis y axis)