Comment 34 for bug 1559576

Phew! Just done all 48 of these tests...

Tests:

1. GDM starts
2. Lightdm starts
3. Can launch Gnome
4. Can launch Gnome Classic
5. External monitor with Lightdm
6. External monitor with Gdm
7. External monitor with Gnome
8. External monitor with Gnome Classic

Results: . is fine, E is error (caused hang), F is fail but not hang. S is skipped, e.g. couldn't get to that test.

Variables:

- graphics driver
- prime select, one of:
  - intel (530 Skylake GT2)
  - NVIDIA Corporation GM107M [GeForce GTX 960M]

Results
---------------------------------------------------
Config Driver Prime 12345678
---------------------------------------------------
c1 361.42-0ubuntu2 intel ....EF*F
c2 361.42-0ubuntu2 nvidia F....FFF
c3 361.42-0ubuntu0~gpu16.04.1 intel ....FFEE
c4 361.42-0ubuntu0~gpu16.04.1 nvidia F....FFF
c5 364.19-0ubuntu0~gpu16.04.1 intel .....FEE
c6 364.19-0ubuntu0~gpu16.04.1 nvidia F.FF?SSS
---------------------------------------------------

## Config 1 ##

- 7:* Probably an E. I had it as a pass because when one monitor is ON it
  works, but having done the other tests I realised that the hang comes when
  two are turned on at once, which was not something I tested here.

- 5:E With monitor plugged in, working under Gnome, logging out to LightDm
  caused hang. Also booting to lightdm with hdmi monitor caused hang.

- 6:F. gdm goes blinky on laptop, unusable with external screen plugged in. See
  note below, seems to be the same problem: can't do two screens at once.
  Unplugging restores a working laptop screen.

- 8:F on test 8 first plugin of monitor caused blank screens. Unplug, replug gave
  an image on the external, laptop turned off. Nb. I had the 'Displays' config
  ui up the 2nd time I plugged in, not sure if this makes any difference. This
  is working. But trying to turn them both on at once resulted in a flashing
  unusable display on the laptop

## Config 2 ##

- 1:F gdm gives completely black screen. Can swap to tty, system not dead.

- 7:F both screens blank, laptop one twitches a bit. Removing cable brought
  back system.

- 8:F as 7:F, but when unplugged needed to swap to tty and back to get
  functioning mouse/interface.

- 6:F as for 1:F

## Config 3 ##

- 5:F lightdm goes all black/flickery when external monitor plugged in.
  Recoverable, though.

- 6:F gdm like lightdm when external monitor plugged in.

- 7:E, 8:E **gnome works on one screen**, but selecting both on causes a
  complete hang.

## Config 4 ##

- 1:F black screen. Pressing power button does cause normal shutdown

- 7:F both go black. Recovered after unplug.

- 8:F as 7:F

## Config 5 ##

- 6:F flashy screen, mostly blank. Removing cable (quickly) brought stability.

- 7:E, 8:E ext. monitor works but hang if 2 displays at once.

## Config 6 ##

Was all the same.

## Conclusions ##

- GDM: intel only across the three drivers.

- Gnome/Gnome classic behave the same.

- Two monitors:

  - both on: you just can't have it with gnome. (lightdm works, and previously
    I had Unity working, too)

  - one on: works with intel, not nvidia.