Comment 3 for bug 317144

Are you using KDE? I suspect this is (yet another) duplicate of bug 278471. Basically, a few monitors go black when information about it is being probed (known as DDC or EDID). The current KDE version has a daemon that probes this information every 10 seconds. Some lines are also dumped to Xorg.0.log at the same time, and you seem to have the same lines repeating over and over again in that file (that happens to everyone, see bug 299492, but only some monitors blink).

To verify that this is what happens, you can run
`while true; do wc -l /var/log/Xorg.0.log; sleep 1; done` (without ``)
This will show print the number of lines in Xorg.0.log every second. You can stop it with Ctrl+C. If it increases just when the monitor blinks, it's a good indication that this is the culprit.

Another detail I noticed is that when I run
`sudo get-edid | parse-edid`
(you will need the read-edid package for this) one of the lines I get is
 Screen is not blanked during DDC transfer
So it seems the montor has a means to advertise that it is blanked during DDC transfers. Possibly yours will do that.

As a possible workaround, you can take a look at the first comment of bug 296481.

If you don't use KDE or otherwise don't think this is duplicate of bug 278471, please include the output of the command `lspci -vvnn`.