Eu estava no Jessie, fiz um upgrade para o Stretch e imediatamente para o Buster. Acredito que tenho o gerenciador de desktop gnome 3 padrão. Se eu bloquear a tela com super-l, não poderei ativá-la novamente com o mouse ou o teclado (mas o scroll lock/num lock alterna os LEDs do teclado). Isso também acontece se eu não fizer login após a inicialização, a tela de login será bloqueada automaticamente após 5 minutos. Acho que os 5 minutos vêm de org.gnome.desktop.session idle-delay uint32 300, portanto, definir isso como 0 pode impedir o bloqueio automático, mas isso não explica por que ele não liga novamente. Observe que a máquina não suspende, apenas desliga o monitor. Acredito que desativei a suspensão com org.gnome.settings-daemon.plugins.power sleep-inactive-ac-type 'nothing'. Este é um desktop, sempre com CA, nunca com bateria.
Posso trazer a tela de volta pelo ssh com:
sudo systemctl restart gdm.service
Algumas gsettings que podem indicar algo:
$ gsettings list-recursively org.gnome.desktop.screensaver
org.gnome.desktop.screensaver picture-opacity 100
org.gnome.desktop.screensaver logout-enabled false
org.gnome.desktop.screensaver lock-enabled false
org.gnome.desktop.screensaver logout-delay uint32 7200
org.gnome.desktop.screensaver embedded-keyboard-enabled false
org.gnome.desktop.screensaver primary-color '#023c88'
org.gnome.desktop.screensaver idle-activation-enabled true
org.gnome.desktop.screensaver secondary-color '#5789ca'
org.gnome.desktop.screensaver logout-command ''
org.gnome.desktop.screensaver color-shading-type 'solid'
org.gnome.desktop.screensaver embedded-keyboard-command ''
org.gnome.desktop.screensaver picture-options 'zoom'
org.gnome.desktop.screensaver lock-delay uint32 0
org.gnome.desktop.screensaver show-full-name-in-top-bar true
org.gnome.desktop.screensaver picture-uri 'file:///usr/share/images/desktop-base/desktop-lockscreen.xml'
org.gnome.desktop.screensaver status-message-enabled true
org.gnome.desktop.screensaver user-switch-enabled true
$ gsettings list-recursively org.gnome.desktop.session
org.gnome.desktop.session session-name 'gnome'
org.gnome.desktop.session idle-delay uint32 0
$ gsettings list-recursively org.gnome.desktop.lockdown
org.gnome.desktop.lockdown disable-command-line false
org.gnome.desktop.lockdown disable-application-handlers false
org.gnome.desktop.lockdown disable-user-switching false
org.gnome.desktop.lockdown user-administration-disabled false
org.gnome.desktop.lockdown disable-printing false
org.gnome.desktop.lockdown disable-log-out false
org.gnome.desktop.lockdown disable-lock-screen false
org.gnome.desktop.lockdown disable-print-setup false
org.gnome.desktop.lockdown disable-save-to-disk false
org.gnome.settings-daemon.plugins.power power-button-action 'interactive'
org.gnome.settings-daemon.plugins.power idle-dim true
org.gnome.settings-daemon.plugins.power sleep-inactive-ac-type 'nothing'
org.gnome.settings-daemon.plugins.power sleep-inactive-battery-timeout 1800
org.gnome.settings-daemon.plugins.power sleep-inactive-battery-type 'nothing'
org.gnome.settings-daemon.plugins.power sleep-inactive-ac-timeout 3600
org.gnome.settings-daemon.plugins.power ambient-enabled true
org.gnome.settings-daemon.plugins.power idle-brightness 30
$ sudo -u Debian-gdm gsettings list-recursively org.gnome.desktop.screensaver
org.gnome.desktop.screensaver picture-opacity 100
org.gnome.desktop.screensaver logout-enabled false
org.gnome.desktop.screensaver lock-enabled true
org.gnome.desktop.screensaver logout-delay uint32 7200
org.gnome.desktop.screensaver embedded-keyboard-enabled false
org.gnome.desktop.screensaver primary-color '#023c88'
org.gnome.desktop.screensaver idle-activation-enabled true
org.gnome.desktop.screensaver secondary-color '#5789ca'
org.gnome.desktop.screensaver logout-command ''
org.gnome.desktop.screensaver color-shading-type 'solid'
org.gnome.desktop.screensaver embedded-keyboard-command ''
org.gnome.desktop.screensaver picture-options 'zoom'
org.gnome.desktop.screensaver lock-delay uint32 0
org.gnome.desktop.screensaver show-full-name-in-top-bar true
org.gnome.desktop.screensaver picture-uri 'file:///usr/share/images/desktop-base/desktop-lockscreen.xml'
org.gnome.desktop.screensaver status-message-enabled true
org.gnome.desktop.screensaver user-switch-enabled true
$ sudo -u Debian-gdm gsettings list-recursively org.gnome.desktop.session
org.gnome.desktop.session session-name 'gnome'
org.gnome.desktop.session idle-delay uint32 300
$ sudo -u Debian-gdm gsettings list-recursively org.gnome.desktop.lockdown
org.gnome.desktop.lockdown disable-command-line false
org.gnome.desktop.lockdown disable-application-handlers false
org.gnome.desktop.lockdown disable-user-switching false
org.gnome.desktop.lockdown user-administration-disabled false
org.gnome.desktop.lockdown disable-printing false
org.gnome.desktop.lockdown disable-log-out false
org.gnome.desktop.lockdown disable-lock-screen false
org.gnome.desktop.lockdown disable-print-setup false
org.gnome.desktop.lockdown disable-save-to-disk false
$ sudo -u Debian-gdm gsettings list-recursively org.gnome.settings-daemon.plugins.power
org.gnome.settings-daemon.plugins.power power-button-action 'suspend'
org.gnome.settings-daemon.plugins.power idle-dim true
org.gnome.settings-daemon.plugins.power sleep-inactive-ac-type 'nothing'
org.gnome.settings-daemon.plugins.power sleep-inactive-battery-timeout 1200
org.gnome.settings-daemon.plugins.power sleep-inactive-battery-type 'suspend'
org.gnome.settings-daemon.plugins.power sleep-inactive-ac-timeout 1200
org.gnome.settings-daemon.plugins.power ambient-enabled true
org.gnome.settings-daemon.plugins.power idle-brightness 30
Atualizar
Editei /etc/gdm3/daemon.conf e descomentei WaylandEnable=false:
[daemon]
# Uncomment the line below to force the login screen to use Xorg
WaylandEnable=false
Agora a tela aparece corretamente quando pressiono uma tecla. Então parece que é algo relacionado a Wayland. Não tenho ideia de como depurá-lo ou de como ativar o registro mais detalhado para tentar restringir o problema.
Mais informações:
$ sudo lspci -nnk | egrep "VGA|3D|Display" -A2
0b:07.0 VGA compatible controller [0300]: Advanced Micro Devices, Inc. [AMD/ATI] ES1000 [1002:515e] (rev 02)
Subsystem: Dell PowerEdge T300 Embedded ATI ES1000 [1028:0210]
Kernel driver in use: radeon