My journalctl is full of these:
lapkr. 09 16:18:30 platonas org.gnome.SettingsDaemon.MediaKeys.desktop[5239]: [5695:5695:1109/161830.225054:ERROR:gl_surface_presentation_helper.cc(237)] GetVSyncParametersIfAvailable() failed!
lapkr. 09 16:18:30 platonas org.gnome.SettingsDaemon.MediaKeys.desktop[5239]: [5695:5695:1109/161830.227435:ERROR:gl_surface_presentation_helper.cc(237)] GetVSyncParametersIfAvailable() failed!
lapkr. 09 16:18:30 platonas org.gnome.SettingsDaemon.MediaKeys.desktop[5239]: [5695:5695:1109/161830.242628:ERROR:gl_surface_presentation_helper.cc(237)] GetVSyncParametersIfAvailable() failed!
lapkr. 09 16:18:30 platonas org.gnome.SettingsDaemon.MediaKeys.desktop[5239]: [5695:5695:1109/161830.248687:ERROR:gl_surface_presentation_helper.cc(237)] GetVSyncParametersIfAvailable() failed!
lapkr. 09 16:18:30 platonas org.gnome.SettingsDaemon.MediaKeys.desktop[5239]: [5695:5695:1109/161830.258811:ERROR:gl_surface_presentation_helper.cc(237)] GetVSyncParametersIfAvailable() failed!
lapkr. 09 16:18:33 platonas org.gnome.SettingsDaemon.MediaKeys.desktop[5239]: [5695:5695:1109/161833.228289:ERROR:gl_surface_presentation_helper.cc(237)] GetVSyncParametersIfAvailable() failed!
lapkr. 09 16:18:33 platonas org.gnome.SettingsDaemon.MediaKeys.desktop[5239]: [5695:5695:1109/161833.242794:ERROR:gl_surface_presentation_helper.cc(237)] GetVSyncParametersIfAvailable() failed!
lapkr. 09 16:18:33 platonas org.gnome.SettingsDaemon.MediaKeys.desktop[5239]: [5695:5695:1109/161833.379889:ERROR:gl_surface_presentation_helper.cc(237)] GetVSyncParametersIfAvailable() failed!
lapkr. 09 16:18:33 platonas org.gnome.SettingsDaemon.MediaKeys.desktop[5239]: [5695:5695:1109/161833.392316:ERROR:gl_surface_presentation_helper.cc(237)] GetVSyncParametersIfAvailable() failed!
lapkr. 09 16:18:34 platonas org.gnome.SettingsDaemon.MediaKeys.desktop[5239]: [5695:5695:1109/161834.560700:ERROR:gl_surface_presentation_helper.cc(237)] GetVSyncParametersIfAvailable() failed!
lapkr. 09 16:18:34 platonas org.gnome.SettingsDaemon.MediaKeys.desktop[5239]: [5695:5695:1109/161834.575089:ERROR:gl_surface_presentation_helper.cc(237)] GetVSyncParametersIfAvailable() failed!
lapkr. 09 16:18:43 platonas org.gnome.SettingsDaemon.MediaKeys.desktop[5239]: [5695:5695:1109/161843.046966:ERROR:gl_surface_presentation_helper.cc(237)] GetVSyncParametersIfAvailable() failed!
lapkr. 09 16:18:43 platonas org.gnome.SettingsDaemon.MediaKeys.desktop[5239]: [5695:5695:1109/161843.058493:ERROR:gl_surface_presentation_helper.cc(237)] GetVSyncParametersIfAvailable() failed!
lapkr. 09 16:18:44 platonas org.gnome.SettingsDaemon.MediaKeys.desktop[5239]: [5695:5695:1109/161844.250630:ERROR:gl_surface_presentation_helper.cc(237)] GetVSyncParametersIfAvailable() failed!
lapkr. 09 16:18:44 platonas org.gnome.SettingsDaemon.MediaKeys.desktop[5239]: [5695:5695:1109/161844.252612:ERROR:gl_surface_presentation_helper.cc(237)] GetVSyncParametersIfAvailable() failed!
lapkr. 09 16:18:44 platonas org.gnome.SettingsDaemon.MediaKeys.desktop[5239]: [5695:5695:1109/161844.258635:ERROR:gl_surface_presentation_helper.cc(237)] GetVSyncParametersIfAvailable() failed!
lapkr. 09 16:18:44 platonas org.gnome.SettingsDaemon.MediaKeys.desktop[5239]: [5695:5695:1109/161844.258812:ERROR:gl_surface_presentation_helper.cc(237)] GetVSyncParametersIfAvailable() failed!
lapkr. 09 16:18:46 platonas org.gnome.SettingsDaemon.MediaKeys.desktop[5239]: [5695:5695:1109/161846.572135:ERROR:gl_surface_presentation_helper.cc(237)] GetVSyncParametersIfAvailable() failed!
lapkr. 09 16:18:46 platonas org.gnome.SettingsDaemon.MediaKeys.desktop[5239]: [5695:5695:1109/161846.575212:ERROR:gl_surface_presentation_helper.cc(237)] GetVSyncParametersIfAvailable() failed!
lapkr. 09 16:18:46 platonas org.gnome.SettingsDaemon.MediaKeys.desktop[5239]: [5695:5695:1109/161846.591944:ERROR:gl_surface_presentation_helper.cc(237)] GetVSyncParametersIfAvailable() failed!
lapkr. 09 16:18:49 platonas org.gnome.SettingsDaemon.MediaKeys.desktop[5239]: [5695:5695:1109/161849.955126:ERROR:gl_surface_presentation_helper.cc(237)] GetVSyncParametersIfAvailable() failed!
lapkr. 09 16:18:49 platonas org.gnome.SettingsDaemon.MediaKeys.desktop[5239]: [5695:5695:1109/161849.958343:ERROR:gl_surface_presentation_helper.cc(237)] GetVSyncParametersIfAvailable() failed!
lapkr. 09 16:18:49 platonas org.gnome.SettingsDaemon.MediaKeys.desktop[5239]: [5695:5695:1109/161849.974856:ERROR:gl_surface_presentation_helper.cc(237)] GetVSyncParametersIfAvailable() failed!
lapkr. 09 16:18:51 platonas org.gnome.SettingsDaemon.MediaKeys.desktop[5239]: [5695:5695:1109/161851.538471:ERROR:gl_surface_presentation_helper.cc(237)] GetVSyncParametersIfAvailable() failed!
lapkr. 09 16:18:51 platonas org.gnome.SettingsDaemon.MediaKeys.desktop[5239]: [5695:5695:1109/161851.541991:ERROR:gl_surface_presentation_helper.cc(237)] GetVSyncParametersIfAvailable() failed!
In total `journalctl -b _COMM=gsd-media-keys | wc -l` reports 231309 such messages since Oct 6, 19:08:54 (i.e. nearly 10 thousand per day).
This makes it a bit difficult to use journalctl to see what other programs are doing, with gsd-media-keys screaming for attention.
ProblemType: Bug
DistroRelease: Ubuntu 18.10
Package: gnome-settings-daemon 3.30.1.2-1ubuntu2
ProcVersionSignature: Ubuntu 4.18.0-10.11-generic 4.18.12
Uname: Linux 4.18.0-10-generic x86_64
NonfreeKernelModules: zfs zunicode zavl icp zcommon znvpair
ApportVersion: 2.20.10-0ubuntu13
Architecture: amd64
CurrentDesktop: GNOME
Date: Fri Nov 9 16:24:04 2018
InstallationDate: Installed on 2016-09-10 (790 days ago)
InstallationMedia: Ubuntu-GNOME 16.04.1 LTS "Xenial Xerus" - Release amd64 (20160720)
SourcePackage: gnome-settings-daemon
UpgradeStatus: Upgraded to cosmic on 2018-10-18 (21 days ago)