Bug 479630

It does sound like there may be a hardware issue here, but it's not possible for changing the resolution to trigger that issue. Likely it's a coincidence or simply the proximate cause rather the root cause, and instead what happened was that the hardware became damaged in another way--e.g. due to excessive heat buildup near the GPU caused by insufficient cooling performance. Either way it sounds like you need to contact the vendor for support.

Out of curiosity, could you share a link to the laptop itself? I ask because it sounds like the issue is similar to an issue a colleague of mine had which was ultimately traced to a hardware design flaw (GPU cable too close to internal heat pipe) and if you've got the same laptop, I'm willing to bet you're suffering from the consequences of the same design flaw.

My laptop is an IdeaPad 5 Pro 16ACH6 with the following specs
https://psref.lenovo.com/Product/IdeaPad/IdeaPad_5_Pro_16ACH6

Processor: AMD Ryzen 5 5600H
Graphics: AMD Radeon Graphics (integrated graphics)
Memory: 8GB soldered memory (DDR4-3200)
Display: 16" 2.5K (2560x1600) IPS 60Hz

I doubt it was a heat issue though. If I had to guess AMD's drivers probably are buggy and KDE Plasma did something that triggered the bug. I have encountered driver bugs with AMD in the past such as this one https://bugs.chromium.org/p/chromium/issues/detail?id=1463267 which AMD said that they will have fixed in their January driver update (this month). 

After letting my laptop sit overnight the vertical and horizontal lines are gone, however the display is still flickery. However it is less flickery than it was yesterday. Its doing a pattern of flickering in quick succession for 1 second, stops flickering for half a second, and then flickering in quick succession for a second again. So I'm hoping this means it will continue to go more back to normal over time. I've been using this laptop for 2 years and have never had this problem before. I would try installing Kubuntu again to see if this is a replicable behavior, but I since the lines are gone and flickering lessened my laptop is kinda usable again and I don't want to risk breaking it more.

Ok, so not the same hardware. However I'm still not super surprised given that IdeaPad is Lenovo's budget line which is not known for its high build or cooling quality. My last IdeaPad did not survive for long which put me off the whole product line, and now I only buy ThinkPads which last much longer. Since the problem has gotten better overnight, I do still suspect a hardware issue related to heat buildup. But you'd be better off contacting Lenovo I think--especially since you said the issue also happens in Windows.

(In reply to vxs2005 from comment #2)
> My laptop is an IdeaPad 5 Pro 16ACH6 with the following specs
> https://psref.lenovo.com/Product/IdeaPad/IdeaPad_5_Pro_16ACH6
> 
> Processor: AMD Ryzen 5 5600H
> Graphics: AMD Radeon Graphics (integrated graphics)
> Memory: 8GB soldered memory (DDR4-3200)
> Display: 16" 2.5K (2560x1600) IPS 60Hz
> 
> I doubt it was a heat issue though. If I had to guess AMD's drivers probably
> are buggy and KDE Plasma did something that triggered the bug. I have
> encountered driver bugs with AMD in the past such as this one
> https://bugs.chromium.org/p/chromium/issues/detail?id=1463267 which AMD said
> that they will have fixed in their January driver update (this month). 
> 
> After letting my laptop sit overnight the vertical and horizontal lines are
> gone, however the display is still flickery. However it is less flickery
> than it was yesterday. Its doing a pattern of flickering in quick succession
> for 1 second, stops flickering for half a second, and then flickering in
> quick succession for a second again. So I'm hoping this means it will
> continue to go more back to normal over time. I've been using this laptop
> for 2 years and have never had this problem before. I would try installing
> Kubuntu again to see if this is a replicable behavior, but I since the lines
> are gone and flickering lessened my laptop is kinda usable again and I don't
> want to risk breaking it more.

Hi, I'm the colleague he spoke about. I have a different laptop from you (Eluktronics THINN 15 with Ryzen 7 4800H), but this sounds just like what I experienced. For a long time my laptop was fine, but then one day temperatures around 80C started causing my display to go black or flicker rapidly. As the laptop cooled down, the flickering slowed and the flickering would appear as noise on the screen just like in your pictures until it finally went back to normal. 80C isn't particularly cool, nor is it what I'd consider overheating. It's normal when the CPU and/or GPU is working hard, but it must have been too much for the cable near the heat pipe after using my laptop for CPU intensive work for 2 years (you also said you had your laptop for 2 years). This doesn't mean that 80C is your laptop's threshold for triggering the issue, I'm just saying your issue sounds similar to my issue. Ultimately, sending my laptop to the manufacturer to get it repaired completely fixed the issue.

After another few hours have gone by the flickering effect on my screen is completely gone. 

To test if overheating was the issue I ran both CPU-Z and Heaven Benchmark at the same time and kept track of temperature using Core Temp. At first my temp jumped to 71C and then both the CPU and GPU started thermal throttling and the temperature wouldn't go any higher. So I went into my bios and put my laptop into "extreme performance" mode and did the same process over again. This time the temperature settled at 81C without thermal throttling. But I wanted to see if it would glitch if I got it even hotter so I covered my laptop's air vent with a piece of cloth and then temperature crept up to 100C and after it reached 100C it started thermal throttling again. But despite reaching 100C no graphical anomalies occured and my laptop is functioning normally.

https://github.com/vExcess/files/blob/main/100C.png

@Noah Davis
I noticed that even when my screen has noise on it, if I use screen recording the noise doesn't appear in the recording. Would this indicate that it's a display problem rather than a graphics card problem? I'm not too familiar with hardware, but I would assume if the noise was happening on the GPU then it would also appear in the screen recording.

(In reply to vxs2005 from comment #6)
> @Noah Davis
> I noticed that even when my screen has noise on it, if I use screen
> recording the noise doesn't appear in the recording. Would this indicate
> that it's a display problem rather than a graphics card problem? I'm not too
> familiar with hardware, but I would assume if the noise was happening on the
> GPU then it would also appear in the screen recording.

I'm not a graphics technology expert, so I couldn't say exactly what things like drivers or firmware affect, but it indicates that everything is OK on the software side (the part that generates graphics before it is sent to hardware to be displayed).