This sounds like the classic issue with monitor sleep. I disable both Monitor and System sleep and this seems to avoid the issue, even in those cases where I am feeding the systems through HDMI, DVI and VGA KVMs. Yea, this does waste power, I have to admit. You could try disabling just Monitor Sleep and see if this is enough...
Hope this helps,
Thank you for the replies/suggestions - I will give it a try next reboot - the only way I can find to do that is via a boot parameter for linux. I will update to let you know how it goes.
I do have one of the machines local now and noticed that console log statements bring the signal back -
Thanks for your patience - here is some more information:
1. consoleblank=0 on boot line may help with bios 54 - but not 100% certain as screen permanently blanked once over the past couple of weeks with machine still up.
2. I have another machine (arrived with bios 57) that nothing seems to helps with. If it loses signal on HDMI or VGA it will blank out and never wake up independent of boot line parameters. Machine is still functioning just fine - just no display output.
3. I have another machine (bios version unknown - will check next time it boots) that I never added anything to boot parameters and it seems to work fine - it just got moved to a KVM - so will keep an eye on it..
The above three machines are all the 5CPYH running ubuntu 16.04
Not extensive test results - but I do believe there is something not functioning correctly with VGA/display drivers in linux.
Others are/have experienced problems with other NUCs - see https://communities.intel.com/thread/96506 - they have had problems with a couple of the NUCs (the i5 and the DC53427hye) - not clear what the outcome was there.
hhj, thanks for the update.
Have you tried to get more feedback from Ubuntu Forums? This I would recommend since Intel provides limited support to Linux and in fact Ubuntu has not been validated to work with this Intel® NUC model.
Supported operating system for Intel® NUC Kit: Supported Operating Systems for Intel® NUC Products