HDMI no longer reported by xrandr (new DELL laptop Intel / AMD Topaz)

Question

HDMI output on second monitor used to work like a charm. Probably after installing compizconfig (trying to solve screen tearing, didn't work out anyway) HDMI output is not working

1. I uninstalled compizconfig completely, nothing.
2. I installed Intel Graphics Update tool, updated everything. Nothing.
3. I did sudo update & upgrade, everything up-to-date. Nothing.

4. xrandr doesn't show any HDMI, only eDP-1:

   bill@bill-Inspiron-5767:~/aeolus$ xrandr
   Screen 0: minimum 320 x 200, current 1920 x 1080, maximum 8192 x 8192
   eDP-1 connected primary 1920x1080+0+0 (normal left inverted right x axis y axis) 381mm x 214mm
      1920x1080     60.00*+  59.93    48.07  
      1680x1050     59.95    59.88  
      1600x1024     60.17...
   ...
   

I am also puzzled by lshw -C display output:

bill@bill-Inspiron-5767:~/aeolus$ sudo lshw -C display
[sudo] password for bill: 
  *-display               
       description: VGA compatible controller
       product: Intel Corporation
       vendor: Intel Corporation
       physical id: 2
       bus info: pci@0000:00:02.0
       version: 02
       width: 64 bits
       clock: 33MHz
       capabilities: pciexpress msi pm vga_controller bus_master cap_list rom
       configuration: driver=i915 latency=0
       resources: irq:280 memory:de000000-deffffff memory:b0000000-bfffffff ioport:f000(size=64) memory:c0000-dffff
  *-display
       description: Display controller
       product: Topaz XT [Radeon R7 M260/M265]
       vendor: Advanced Micro Devices, Inc. [AMD/ATI]
       physical id: 0
       bus info: pci@0000:01:00.0
       version: c3
       width: 64 bits
       clock: 33MHz
       capabilities: pm pciexpress msi bus_master cap_list rom
       configuration: driver=amdgpu latency=0
       resources: irq:281 memory:c0000000-cfffffff memory:d0000000-d01fffff ioport:e000(size=256) memory:df200000-df23ffff memory:df240000-df25ffff

What on earth does this mean? Do I have 2 graphics cards? Do I need to update that Topaz XT graphics driver to re-enable HDMI?

EDIT : About computer reports:

Graphics : Intel® HD Graphics 620 (Kabylake GT2)

Answer 1

After a few random updates, upgrades and reboots, the HDMI started working again. It may have halped that, among Ubuntu reboots, I also booted Windows 10 (dual boot) to check that there's no hardware problem (there wasn't).

The funny thing was that, after getting the screen, Ubuntu started up but neither keyboards nor mice and touchpad would work!!!

So I had to fix that too. I followed this solution to go to GRUB->Secure, enable networking and install missing input packages: https://askubuntu.com/a/910211/509917