It doesn't seem like the screensaver really is properly disabled during upgrades, at least looking very naively at what happens during the upgrade -- if I go out of my way to disable it, I got the screen to completely freeze (but at least everything did not crash down to lightdm).
FWIW, I've managed to somewhat make sure the issues were in one of this set for upgrade:
The following packages will be REMOVED:
gnome-system-monitor libatkmm-1.6-1 libcairomm-1.0-1 libglibmm-2.4-1c2a
libgtkmm-3.0-1 libmetacity-private0a libpangomm-1.4-1 libsigc++-2.0-0c2a
overlay-scrollbar-gtk3
The following NEW packages will be installed:
adwaita-icon-theme gcc-5-base jayatana libappstream-glib8
libboost-filesystem1.58.0 libboost-system1.58.0 libcolord2 libgcab-1.0-0
libgcrypt20 libglew1.13 libglewmx1.13 libglibmm-2.4-1v5
libgnome-desktop-3-12 libgtop-2.0-10 libmetacity-private3a libmirclient9
libmircommon5 libmirprotobuf3 libprotobuf-lite9v5 libprotobuf9v5
libsigc++-2.0-0v5 libsystemd0 libyaml-0-2 session-shortcuts unity-schemas
The following packages will be upgraded:
bamfdaemon compiz-core compiz-gnome compiz-plugins-default fontconfig-config
gnome-accessibility-themes gnome-desktop3-data indicator-appmenu libatk1.0-0
libatk1.0-data libbamf3-2 libcairo2 libcompizconfig0 libdecoration0
libfontconfig1 libgail-3-0 libgpg-error0 libgtk-3-0 libgtk-3-common
libgtop2-common libharfbuzz0b liblcms2-2 libnux-4.0-0 libnux-4.0-common
libpango-1.0-0 libpango1.0-0 libpangocairo-1.0-0 libpangoft2-1.0-0
libpangoxft-1.0-0 libsoup2.4-1 libstdc++6 libunity-core-6.0-9
libunity-protocol-private0 libunity9 libwayland-client0 libwayland-cursor0
libxkbcommon0 libxrandr2 metacity-common overlay-scrollbar ubuntu-desktop
unity unity-services
43 upgraded, 25 newly installed, 9 to remove and 1262 not upgraded.
Need to get 17.9 MB of archives.
After this operation, 12.2 MB of additional disk space will be used.
It certainly still points to an issue in compiz and needs further debugging, but I'll let Eleni deal with it and focus on the screensaver bits in u-r-u, at least to make sure it does disable the screensaver correctly and that I was just mistaken.
It doesn't seem like the screensaver really is properly disabled during upgrades, at least looking very naively at what happens during the upgrade -- if I go out of my way to disable it, I got the screen to completely freeze (but at least everything did not crash down to lightdm).
FWIW, I've managed to somewhat make sure the issues were in one of this set for upgrade: system- monitor libatkmm-1.6-1 libcairomm-1.0-1 libglibmm-2.4-1c2a private0a libpangomm-1.4-1 libsigc++-2.0-0c2a scrollbar- gtk3 icon-theme gcc-5-base jayatana libappstream-glib8 filesystem1. 58.0 libboost- system1. 58.0 libcolord2 libgcab-1.0-0 desktop- 3-12 libgtop-2.0-10 libmetacity- private3a libmirclient9 plugins- default fontconfig-config accessibility- themes gnome-desktop3-data indicator-appmenu libatk1.0-0 protocol- private0 libunity9 libwayland-client0 libwayland-cursor0
The following packages will be REMOVED:
gnome-
libgtkmm-3.0-1 libmetacity-
overlay-
The following NEW packages will be installed:
adwaita-
libboost-
libgcrypt20 libglew1.13 libglewmx1.13 libglibmm-2.4-1v5
libgnome-
libmircommon5 libmirprotobuf3 libprotobuf-lite9v5 libprotobuf9v5
libsigc++-2.0-0v5 libsystemd0 libyaml-0-2 session-shortcuts unity-schemas
The following packages will be upgraded:
bamfdaemon compiz-core compiz-gnome compiz-
gnome-
libatk1.0-data libbamf3-2 libcairo2 libcompizconfig0 libdecoration0
libfontconfig1 libgail-3-0 libgpg-error0 libgtk-3-0 libgtk-3-common
libgtop2-common libharfbuzz0b liblcms2-2 libnux-4.0-0 libnux-4.0-common
libpango-1.0-0 libpango1.0-0 libpangocairo-1.0-0 libpangoft2-1.0-0
libpangoxft-1.0-0 libsoup2.4-1 libstdc++6 libunity-core-6.0-9
libunity-
libxkbcommon0 libxrandr2 metacity-common overlay-scrollbar ubuntu-desktop
unity unity-services
43 upgraded, 25 newly installed, 9 to remove and 1262 not upgraded.
Need to get 17.9 MB of archives.
After this operation, 12.2 MB of additional disk space will be used.
It certainly still points to an issue in compiz and needs further debugging, but I'll let Eleni deal with it and focus on the screensaver bits in u-r-u, at least to make sure it does disable the screensaver correctly and that I was just mistaken.