Sorry, that doesn't do it yet. (Shame I didn't manage to fix this for 5.0.0.) However I realised that Mesa has exactly the same problem, so I have taken a look at their code to see what they do. Also looks like a bit of a hack, but since nothing relevant can afford not to work with Mesa it should be a safe one.
-- You received this bug notification because you are a member of Ubuntu Touch seeded packages, which is subscribed to lightdm in Ubuntu. https://bugs.launchpad.net/bugs/1599775 Title: "low-graphics mode" in VirtualBox guest, but X server running Status in lightdm package in Ubuntu: New Bug description: I sometimes get the "low-graphics mode" message when starting an Ubuntu 16.04 virtual machine inside of VirtualBox (current development code trunk, somewhere past version 5.1 beta 3 and a debug build). When I switch to VT-7 I find the X server running without any visible issues (I am the upstream developer of the guest graphics drivers, so I have a reasonable but not infallible understanding of the X server). The virtual machine has Guest Additions installed, same vintage and also a debug build. Two screens are enabled as is 3D acceleration. The host system is also Ubuntu 16.04. I am still trying to work out what triggers the message, but in my last attempts a cold boot failed to produce it, while a clean reboot did, but only when the host system was not under load (under load as in building VirtualBox). Searching the lightdm log files led me to the message "CRITICAL **: session_get_login1_session_id: assertion 'session != NULL' failed", which in turn led me to this similar-looking Debian bug: https://bugs.debian.org/cgi-bin/bugreport.cgi?bug=814760 ProblemType: Bug DistroRelease: Ubuntu 16.04 Package: lightdm 1.18.1-0ubuntu1 ProcVersionSignature: Ubuntu 4.4.0-28.47-generic 4.4.13 Uname: Linux 4.4.0-28-generic x86_64 ApportVersion: 2.20.1-0ubuntu2 Architecture: amd64 CurrentDesktop: Unity Date: Thu Jul 7 10:49:27 2016 InstallationDate: Installed on 2016-06-08 (28 days ago) InstallationMedia: Ubuntu 16.04 LTS "Xenial Xerus" - Release amd64 (20160420.1) SourcePackage: lightdm UpgradeStatus: No upgrade log present (probably fresh install) IRC discussion at: https://irclogs.ubuntu.com/2016/07/07/%23ubuntu-devel.html#t07:52 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/lightdm/+bug/1599775/+subscriptions -- Mailing list: https://launchpad.net/~touch-packages Post to : touch-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~touch-packages More help : https://help.launchpad.net/ListHelp
