Bug 392286

Summary:	Display turns on twice after going into powersaving mode
Product:	[Unmaintained] Powerdevil	Reporter:	Lastique <andysem>
Component:	general	Assignee:	Plasma Bugs List <plasma-bugs-null>
Status:	RESOLVED UPSTREAM
Severity:	normal	CC:	vkrevs
Priority:	NOR
Version First Reported In:	5.10.5
Target Milestone:	---
Platform:	Kubuntu
OS:	Linux
Latest Commit:		Version Fixed/Implemented In:
Sentry Crash Report:

Description Lastique 2018-03-24 21:26:02 UTC

I have two displays attached to my GTX980, the main display on DisplayPort-4 and a secondary display on HDMI-0. The system is configured to turn off the displays after 10 minuses of inactivity.

PowerDevil turns off the displays as expected. However, ~5 minutes after that the main display on DP-4 turns on only to show that there is no signal (the display's  on-screen message) and turns off again. Another ~5 minutes later this happens again. After that the display stays off as it should be. The other display on HDMI-0 is actually a TV and it shows a blank screen all the time with no activity while DP-4 wakes up.

This only happens when the display turns off for power saving. It does not happen if I issue `xset dpms force off` from the command line (the displays turn off and don't wake up). This is 100% reproducible and I'm sure it's not due to some activity (e.g. an event from the mouse) because when the display wakes up it does not show desktop/lock screen.

I would like the display to not wake up like that.

Kubuntu 17.10, x86_64, Nvidia driver 390.42, GTX980, DP-4 display is NEC EA275UHD.

Comment 1 Lastique 2018-12-13 11:28:28 UTC

The problem has been resolved in Nvidia driver 415.x, which introduced the new xorg.conf option "HardDPMS". With this option set to true, the driver will disable the display with modeset instead of one of the powersaving modes, which solves the problem for me.

https://download.nvidia.com/XFree86/Linux-x86_64/415.18/README/xconfigoptions.html#HardDPMS