Most, but not all, boots from cold, I get a Low Graphics Mode error

[Roger Davis]

After an update (kernel?), I have begun to receive the message "Running in Low Graphics Mode" at boot. I can tell it to use Default setting from the options it offers, and get by it, after which things look and work normally until a reboot, which may or may not occur correctly.

If I select extra graphics debug messages and display boot messages in Xdiagnose, this problem DOES NOT occur. If I deselect those, the problem begins again.

I don't know which update caused it, but it was somewhere around mid or early May.

ProblemType: Bug
DistroRelease: Ubuntu 16.04
Package: xorg 1:7.7+13ubuntu3.1
ProcVersionSignature: Ubuntu 4.15.0-32.35~16.04.1-generic 4.15.18
Uname: Linux 4.15.0-32-generic x86_64
.tmp.unity_support_test.0:

ApportVersion: 2.20.1-0ubuntu2.18
Architecture: amd64
CompizPlugins: No value set for `/apps/compiz-1/general/screen0/options/active_plugins'
CompositorRunning: None
Date: Fri Aug 17 12:02:03 2018
DistUpgraded: 2016-12-17 18:57:41,412 DEBUG icon theme changed, re-reading
DistroCodename: xenial
DistroVariant: ubuntu
DkmsStatus:
 virtualbox, 5.1.38, 4.15.0-30-generic, x86_64: installed
 virtualbox, 5.1.38, 4.15.0-32-generic, x86_64: installed
 virtualbox, 5.1.38, 4.4.0-133-generic, x86_64: installed
ExtraDebuggingInterest: Yes
GraphicsCard:
 Advanced Micro Devices, Inc. [AMD/ATI] Cape Verde PRO [Radeon HD 7750/8740 / R7 250E] [1002:683f] (prog-if 00 [VGA controller])
   Subsystem: PC Partner Limited / Sapphire Technology Cape Verde PRO [Radeon HD 7750/8740 / R7 250E] [174b:e213]
InstallationDate: Installed on 2014-07-07 (1502 days ago)
InstallationMedia: Ubuntu 14.04 LTS "Trusty Tahr" - Release amd64 (20140417)
ProcEnviron:
 LANGUAGE=en_US
 PATH=(custom, no user)
 LANG=en_US.UTF-8
 SHELL=/bin/bash
ProcKernelCmdLine: BOOT_IMAGE=/boot/vmlinuz-4.15.0-32-generic root=UUID=3d311d21-7c70-432e-a4ac-d9dd4986a2b5 ro quiet plymouth:debug=1 plymouth:debug=1=1=1=1=1 splash plymouth:debug=1=1=1=1=1=1=1=1=1 plymouth:debug=1=1=1=1=1=1=1=1=1=1=1=1=1 vt.handoff=7
SourcePackage: xorg
UpgradeStatus: Upgraded to xenial on 2016-12-18 (607 days ago)
dmi.bios.date: 02/08/2012
dmi.bios.vendor: Intel Corp.
dmi.bios.version: BHZ7710H.86A.0057.2012.0208.1904
dmi.board.name: DZ77BH-55K
dmi.board.vendor: Intel Corporation
dmi.board.version: AAG39008-400
dmi.chassis.type: 3
dmi.modalias: dmi:bvnIntelCorp.:bvrBHZ7710H.86A.0057.2012.0208.1904:bd02/08/2012:svn:pn:pvr:rvnIntelCorporation:rnDZ77BH-55K:rvrAAG39008-400:cvn:ct3:cvr:
dmi.product.family: To be filled by O.E.M.
version.compiz: compiz 1:0.9.12.3+16.04.20180221-0ubuntu1
version.ia32-libs: ia32-libs N/A
version.libdrm2: libdrm2 2.4.91-2~16.04.1
version.libgl1-mesa-dri: libgl1-mesa-dri 18.0.5-0ubuntu0~16.04.1
version.libgl1-mesa-dri-experimental: libgl1-mesa-dri-experimental N/A
version.libgl1-mesa-glx: libgl1-mesa-glx 18.0.5-0ubuntu0~16.04.1
version.xserver-xorg-core: xserver-xorg-core N/A
version.xserver-xorg-input-evdev: xserver-xorg-input-evdev N/A
version.xserver-xorg-video-ati: xserver-xorg-video-ati N/A
version.xserver-xorg-video-intel: xserver-xorg-video-intel N/A
version.xserver-xorg-video-nouveau: xserver-xorg-video-nouveau N/A
xserver.bootTime: Fri Aug 17 12:00:19 2018
xserver.configfile: default
xserver.devices:

xserver.logfile: /var/log/Xorg.0.log
xserver.outputs:

xserver.version: 2:1.19.6-1ubuntu4~16.04.1