I changed my monitor input source selection from Auto to HDMI (which is the only used connector), and this no longer happens. Since I have a workaround, you can close the issue. If someone else will encounter this issue, I can recreate it and try to provide the missing info (which currently requires some work to do, so is not worth it).
-- You received this bug notification because you are a member of Kernel Packages, which is subscribed to linux in Ubuntu. https://bugs.launchpad.net/bugs/1579579 Title: Monitors immediately come out of energy saving mode Status in linux package in Ubuntu: Expired Bug description: On Kubuntu 16.04 with kernel 4.4.0-22.39-generic 4.4.8, but it's been like this since 15.10 a few kernels back. Multiple screens connected. Intel i7 4771 Haswell with only integrated GPU (no dedicated graphics card). What happens is that the monitors do enter energy saving mode at the configured timeout of user inactivity, but a couple seconds later they snap right out of it. Usually when I come back to my computer after being away there are also a few Plasma crash dialogs. My monitors haven't been saving energy (or pixel life) in over half a year now. The only evidence I found in the system log, which I'm not sure is related but might be worth mentioning, is: [Mon May 9 00:29:03 2016] snd_hda_codec_hdmi hdaudioC0D0: HDMI: ELD buf size is 0, force 128 [Mon May 9 00:29:03 2016] snd_hda_codec_hdmi hdaudioC0D0: HDMI: invalid ELD data byte 0 To manage notifications about this bug go to: https://bugs.launchpad.net/ubuntu/+source/linux/+bug/1579579/+subscriptions -- Mailing list: https://launchpad.net/~kernel-packages Post to : kernel-packages@lists.launchpad.net Unsubscribe : https://launchpad.net/~kernel-packages More help : https://help.launchpad.net/ListHelp