Excessive flickering when opening new programs

[ScottyK]

I have a dual monitor setup, and when I open something on one monitor, there is excessive flickering and flashing on the other monitor. The only way to get it to stop is to move the mouse over to that monitor and click something. It was pretty bad for a while, then last month I did a clean install. It was fine for a few weeks, but I've noticed it's gradually getting bad again. I can't seem to find the file or package that might be causing it. Some days the monitors barely flash and flicker. Other days it's nearly constant, and I have to keep clicking the flashing monitor to get it to stop.

I have a NVidia GTX 1050 Ti, and running driver version 510.54 as provided by the standard repos. Both monitors are connected by either a display port, or HDMI. The system rarely powers down, but I put it in sleep mode every night.

I think I'm still running X-Server, for within Kinfo there is a lot of info about X-Server, but under Wayland it's blank.

Below is a link to a video I made of the flashing/flickering.

KDE Plasma Version - 5.18.8
KDE Frameworks Version - 5.68.0
QT Version - 5.12.8
Kernel Version - 5.13.0-37-generic

https://www.dropbox.com/s/jvspxuleus...18.49.mp4?dl=0

[claydoh]

Bad cable?
bad -ish monitor?
Did this happen on an older/previous driver version?

I have had a very similar issue, maybe even exactly the same. My second monitor randomly went blank, and blinking off and on. I swapped the cable out, though not for a new one, and it still blacked out and blinked. Some days it would be zero issues, some it happened off and on all day. AMD here, though, so no external drivers.

I solved it after a few months by buying a new (refurb) monitor. I have had zero blanking/blinking at all from the moment I connected it, and I am even using the same cable that was on the old monitor.

Just sayin', don't discount hardware. It is not always the OS.

[ScottyK]

It does it on both monitors. However I did a shutdown last night, and so far this morning, It's not doing it.

I've been running 20.04 for a while (no pun intended) and it was fine, just started happening the last couple of months. Then last month when I did the reinstall, the problem went away, only to gradually creep back.

[claydoh]

Driver upgrades perhaps?
Dunno, just grasping at straws. it is possible via the driver manager to downgrade to a lower version. On your 1050, the latest drivers may not be adding much in terms of features or performance.

[Snowhog]

The system rarely powers down, but I put it in sleep mode every night.

That could be the ultimate problem; "rarely powers down". I offer that as a possible cause, as the problem might not be any software or drivers at all; it might be the monitor. How old is it? How long has it been in use?

[oshunluvr]

I'm not sure not powering down would be an issue. My desktop and server haven't been in OFF mode for over a year. However, not rebooting after an major update is a whole different story. Of course, if there's a heat issue, that might be a problem exacerbated by power on hours.

Since it's possibly video related, you might check your cooling fans and case vents for dust bunnies if you haven't already.

[ScottyK]

Good Suggestions everyone, I appreciate it. The cold shutdown last night seems to have done the trick. All day today, not a single flicker or flash. It might not have been rebooted since I reinstalled Kubuntu back in February. Both monitors are a couple of years old (a Samsung and an HP). It's been cleaned inside recently as I installed a new SSD. Cool air coming out of the vents, so it's not over heating. So possibly something got updated, but it needed a reboot to fix/correct something? Don't know, but it's working! I guess the old advice, "Have you turned it off and on" really did help.


So moving forward going to reboot the system every weekend, just to let things update or whatever.

[GreyGeek]

In the "good ole days" rebooting wasn't a requirement unless you installed a new kernel. While I was running SuSE 6.3 on both my server and my minitower they were up for a total of 403 days, IIRC, before I switched to another distro. Back in those days we had an uptime war with Windows users, who claimed uptimes equal or greater than any posted Linux uptime. Then, Microsoft announced the clock bug which would automatically reboot the computer after 49.7 days Opps! The uptime war vanished over night.

These days upgrading or downgrading a kernel or a video driver or some other driver that is built into the kernel requires a reboot.
I turn my laptop off every night to minimize the power on hours of the HDD. Now, it is to minimize the total writes to the SSD. Because everything in Linux is a file, there is always disk I/O taking place, if for no other reason than to update several logs.

[jlittle]

These days upgrading or downgrading a kernel or a video driver or some other driver that is built into the kernel requires a reboot.

Another aspect to this story is that computers, and Linux in particular, boot much more quickly these days, thanks to SSDs and systemd.

[ScottyK]

Update to the story. Put the computer in sleep mode last night, and today the flickering problems are back. So what I seem to observe is - Shutdown, no flickering. Sleep and resume - Flickering.

Going to power it down tonight instead of sleep mode and see what happens tomorrow.

[oshunluvr]

Well at least you're making progress in finding the cause. I wonder what is actually the issue. I don't use "sleep" but I assume it loads from storage back to it's exact state when is was put to sleep.

Try waking up from sleep, logging out and back in.

Or maybe waking up, then restarting SDDM, which reloads the video driver. It could be just a bug in the video driver.

[claydoh]

Driver upgrades perhaps?
Dunno, just grasping at straws. it is possible via the driver manager to downgrade to a lower version. On your 1050, the latest drivers may not be adding much in terms of features or performance.

And worth checking out, if it is a bug in the latest, hot-off-the presses driver version