Comment 28 for bug 869017

Some additional information and observations.

What I am currently seeing with this issue on 3 systems running Ubuntu 18.04 that did not occur on the same systems that previously ran 16.04 is that the actual screen blanking in 18.04, aside from default settings or overrides, fails to turn off the monitor using DPMS as it did in 16.04, but only with nvidia binary drivers installed and only in 18.04, and only with the console blanking code in its current state.

In 18.04 without the nvidia binary driver, console blanking seems to work, as expected, with the consoleblank=n. This includes a correct power down.

In 18.04 with the nvidia binary driver 340.107, console blanking only blanks the screen, but fails to power down the monitor- yet a call to vbetool dpms off does work, as do any similar calls in X for those systems that have X installed. So if vbetool dpms works with the nvidia binary driver and the console blanking code no longer does, I am half way to an assumption that the dpms code in the console blanking has changed, with some reservation that possibly the latest nvidia binary driver doesn't like the way the call is coming from the newly changed console blanking code.

This problem did not exist in 16.04, on any of our systems to my knowledge, with or without a graphical desktop installed and with or without a binary driver installed.

From my perspective, this isn't an issue of default blanking behaviour, but rather an issue with a broken dpms call in 18.04 to a system with the nvidia binary driver. Other calls, such as vbetool dpms off work as do those within graphical desktop systems such as those like the one that xscreensaver uses.