I think this is a regression... I had the exact same problem (system not going to suspend when LID is closed and external monitor plugged-in) with XUbuntu 19.04.
Under Xubuntu 19.04, I was using light-locker and was advised to switch to power manager. This solved the problem.
However, I recently upgraded to XUbuntu 19.10 and now, I get the exact same problem: if my external monitor is plugged-in, then closing the LID the computer does not suspend, it only switches the monitor external monitor to black screen (sleep?) for half a second, then switches it on again.
I've tried the solution provided in the following answer: https://forum.xfce.org/viewtopic.php?id=12970#p52468
With this the external monitor does blank/go to sleep, but the system does not go to suspend on lid close. It *does* go to suspend... *but when the lid is reopened!!!!
I tried to remove power manager and switch back to light-locker. It does not work either.
Hi,
I think this is a regression... I had the exact same problem (system not going to suspend when LID is closed and external monitor plugged-in) with XUbuntu 19.04.
Under Xubuntu 19.04, I was using light-locker and was advised to switch to power manager. This solved the problem.
However, I recently upgraded to XUbuntu 19.10 and now, I get the exact same problem: if my external monitor is plugged-in, then closing the LID the computer does not suspend, it only switches the monitor external monitor to black screen (sleep?) for half a second, then switches it on again.
See demonstration at: /lufi.alolise. org/r/6Qo2m8r2t 9#D1ZYe/ CXqxMAcLD6UZvFl bYNMVfQESfr5j7v xg85MiI=
https:/
light-lock says power manager is responsible for the PM config: /lufi.alolise. org/r/TEn9o2m56 q#WUJDAf/ NYTbaLgbD/ Z5WBQUwVE173dyx 3lhSZZbNvf8=
https:/
Xfce Power Manager is version 1.6.5
I've tried the solution provided in the following answer: /forum. xfce.org/ viewtopic. php?id= 12970#p52468
https:/
With this the external monitor does blank/go to sleep, but the system does not go to suspend on lid close. It *does* go to suspend... *but when the lid is reopened!!!!
I tried to remove power manager and switch back to light-locker. It does not work either.