multi-monitor screen flashing GTX 1050

Question

I have a Ryzen system powered by a GTX 1050 which originally used a triple-monitor setup comprised of two HP 23" 1080p monitors and a 20" 1600x900 Samsung monitor. I used this configuration on both Windows 10 and 18.04 with no issues (using proprietary drivers).

Recently, I needed my Samsung monitor for a separate setup, and detached it from the PC in question. The setup then was comprised of the two HP monitors, one driven via HDMI, the other DP. With this setup, Windows had no issues. However, Ubuntu continually experienced randomly occurring "black screens", wherein one or both monitors would loose signal and turn completely black for less than 2 seconds with no apparent disruption to any other system functions. The displays always recover from their apparent signal loss, and any playing video or audio seem uninterrupted.

Out of curiosity, I reattached the Samsung monitor (DVI) , and the issue was no longer present. I know that is is probably not enough information to solve the problem, but I'm at a loss as to what I should do to at least diagnose what the issue actually is.

Specs:

• Ryzen 5 2400g
• Gigabyte GTX 1050 oc
• Asus B350M-A
• HP 2311xi/Z23I, Samsung SA300

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Update; Here is the output from xrandr with all 3 monitors attached:

Screen 0: minimum 8 x 8, current 5440 x 1080, maximum 32767 x 32767 DVI-D-0 connected 1600x900+3840+0 (normal left inverted right x axis y axis) 443mm x 249mm 1600x900 60.00*+ 1440x900 74.98 59.89
1280x800 74.93 59.81
1280x720 60.00 50.00
1152x864 75.00
1024x768 75.03 70.07 60.00
800x600 75.00 72.19 60.32 56.25
720x576 50.00
720x480 59.94
640x480 75.00 72.81 59.94
HDMI-0 disconnected (normal left inverted right x axis y axis) DP-0 connected primary 1920x1080+1920+0 (normal left inverted right x axis y axis) 509mm x 286mm 1920x1080 60.00*+ 1680x1050 59.95
1600x900 60.00
1440x900 59.89
1280x1024 60.02
1280x720 60.00
1024x768 60.00
800x600 60.32
640x480 59.94
DP-1 disconnected (normal left inverted right x axis y axis) HDMI-1 connected 1920x1080+0+0 (normal left inverted right x axis y axis) 509mm x 286mm 1920x1080 60.00*+ 59.94 50.00
1680x1050 59.95
1440x900 59.89
1280x1024 60.02
1280x720 60.00 59.94 50.00
1024x768 60.00
800x600 60.32
720x576 50.00
720x480 59.94
640x480 59.94 59.93

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Update_2; The random black screens do indeed occur when the Samsung monitor is attached with only one of either of the HP monitors (although seemingly much less frequently, so far I've only noticed it once or twice per uptime within minutes of each boot), however the problem does not persist when only one of the three monitors are connected individually. Also, My system is running the "Tested" 390 driver provided through the Software & Updates app:

Answer 1

When I look up the specs for the monitors I find that they have different refresh rates. The 2311xi is the one I'm most interested in because it runs, according to spec, at a higher refresh rate than the other two. I've personally had issues with monitors for computer builds before -- mainly those that supported high refresh rates. On those (on Windows even) I needed to install monitor profiles in order for them to work properly, black flickering, tearing and complaints like that.

Am I figuring this issue might have to do with the different refresh rates the monitors run at rather than the connector it is running over?

Could you open up a terminal and run xrandr and update your question? Whenever you find that one will prefer a higher refresh rate try xrandr --screen 0 -s 1920x1080 -r 60. Where 1920x1080 is your resolution and screen should be the target screen running higher, you can find the screen number in the initial xrandr as it will show per connected monitor.

You could also try the SA300 and Z23I as a pair and see if the problem still persists if that's possible, these both run at 60Hz. I wouldn't know the connectivity as I don't know what specific SyncMaster model you have.