Comment 1 for bug 1930359

I built a test package based on mutter 3.36.9-0ubuntu0.20.04.1, and reverted the three commits introduced by LP #1905825, namely:

commit: 92834d8feceeac538299a47a8c742e155de4e6e8
From: Kai-Heng Feng <email address hidden>
Date: Mon, 21 Dec 2020 14:34:43 +0800
Subject: renderer/native: Refactor modeset boilerplate into new helpers
Link: https://gitlab.gnome.org/GNOME/mutter/-/commit/92834d8feceeac538299a47a8c742e155de4e6e8

commit: 097af7ddb381606da74c737859cc92fff72ed417
From: Kai-Heng Feng <email address hidden>
Date: Mon, 21 Dec 2020 14:59:32 +0800
Subject: monitor-manager-kms: Disable CRTCs if there is no monitor
Link: https://gitlab.gnome.org/GNOME/mutter/-/commit/097af7ddb381606da74c737859cc92fff72ed417

commit: 93f3ce3c305571bfc39f6d9e5d221e1b60a920a4 Mon Sep 17 00:00:00 2001
From: Kai-Heng Feng <email address hidden>
Date: Fri, 13 Nov 2020 14:19:26 +0800
Subject: monitor-manager-xrandr: Disable CRTCs if there is no monitor
Link: https://gitlab.gnome.org/GNOME/mutter/-/commit/93f3ce3c305571bfc39f6d9e5d221e1b60a920a4

The testpackage is available in [1]:

[1] https://launchpad.net/~mruffell/+archive/ubuntu/sf311791-test

I provided the testpackage to the affected user, and they installed it in a test VDI on their VMware Horizon environment, and wrote back that it works.

So, it seems to be the CRTc changes from bug 1905825.

The affected user's environment uses Nvidia GRID GPUs, passed into the VDI. They are using the Nvidia GRID 450.51.05 driver.

I have been trying to reproduce this for a few days now. Google Cloud has an option to pass a Nvidia P4 GPU into the instance, and turn on Nvidia GRID, so I have been using that platform.

I have tried with gpu, without gpu, multiple versions of mutter, with and without VMware Horizon Viewagent 7.13, but in each of my runs, I see gdm3 running, and I see the usual processes that get spawned off of it. I have tried multiple versions of the Nvidia GRID driver, available from [2], but they appear to act the same.

[2] https://cloud.google.com/compute/docs/gpus/grid-drivers-table

I think I am missing something, but I'm not sure what. I have tried using the "virtual display" feature with and without, and when it is enabled and I view the screenshot, I just see a black screen with a blinking cursor, no matter what mutter package I have installed.

It could be a virtual hotplug might be needed, but I'm not sure how that can be achieved on Google Cloud, or how it would happen on the affected user's VMware Horizon on VMware ESXi environment.

I will ask the affected user for some more logs, so we can better see what is going on.