On 9/10/19 4:30 AM, Miroslav Skoric wrote:
After upgrading the old laptop from Jessie to Stretch, I noticed that
the screensaver in Mate environment does not work for me as before. For
example, when the screen goes black after some time of inactivity, for
returning back it is not enough just to touch the touchpad or press any
key. Instead, pressing any key or touching the touchpad makes the screen
just some 1% lighter than the full black (or better to say, it remains
99% black). However, the last working GUI does not return.
I have this same issue with the default configuration of XFCE on Buster,
where the problem was not present on Stretch.
Is light-locker installed, and do you use lightdm? light-locker appears
to be the source of this issue. Googling "light-locker black screen"
returns dozens of posts across many sites complaining about the same
problem.
I resolved this issue by removing light-locker and installing
xscreensaver instead. Note that this required removing a few
metapackages, and then marking the dependent packages that I wanted to
keep as manually installed to prevent apt from removing most of my
desktop tools.