reproducible on neon dev unstable start wayland session wait your system to reach screen power management timeout after your screen to turn off, wake up it doing double tap do NOT use any input device (touch screen, touchpad, mouse, keyboard) and wait for screen power management timeout again: your screen remains on when the timeout is reached move your cursor, press any key or tap your screen, wait for the timeout again: now your screen turns off
Possible patch at https://phabricator.kde.org/D12668 Any chance to test? The issue and the fix look straight forward to me.
Git commit 69afe4d266ffbde364913d31fbcbc00769b4b390 by Martin Flöser. Committed on 20/05/2018 at 13:38. Pushed by graesslin into branch 'Plasma/5.12'. Update seat's timestamp after waking up screen through double tap Summary: The drm platform has a special handling for touch events while the screen is in dpms. All touch events are filtered out, but a double tap wakes up the screen. Due to the filtering out of the events the idle timers were not reset. So if you only double tapped, the screen turned on, but not off again. This change updates the timestamp after double tap, so that the idle timers are restarted. All other events are still filtered out, to not have "fake" events (e.g. smart phone in pocket) wake up the device. FIXED-IN: 5.12.6 Test Plan: only compile tested Reviewers: #kwin, #plasma Subscribers: kwin Tags: #kwin Differential Revision: https://phabricator.kde.org/D12668 M +4 -1 plugins/platforms/drm/drm_inputeventfilter.cpp https://commits.kde.org/kwin/69afe4d266ffbde364913d31fbcbc00769b4b390