But 25.10 is different on all levels, so there is no telling what the ultimate cause is. Might be the kernel, might just as well be some glitch in KDE, etc.
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I think you should start with the upstream/mainline version of 7.0.0-22, or whatever uname -r says. That way you exclude Ubuntuâs patches. If the issue goes away with the matching upstream kernel, itâs a bug caused by one of those patches; you can stop right away and report it:
ubuntu-bug linux-image-$(uname -r)
(must be run from the affected kernel, not the mainline PPA one)
Once youâve made sure that Ubuntu patching canât be the issue, see if the very latest kernel makes any difference; perhaps a bug/regression has already been fixed. If not, check with 6.17, which is the one from 25.10; since Iâve never used the mainline kernel PPA, I donât know if that is even possible.
@thanksracer I cannot reproduce this on Xubuntu 26.04 or Ubuntu 26.04 with nvidia-driver-595-open (595.71.05). It only happens in Kubuntu 26.04 when my monitor refresh rate is set to 360 Hz (doesnât happen at 60 Hz). What is your refresh rate? I see some other threads here in support category where users are reporting similar issues, so this must be a widespread thing. Curious to know why different DEâs are affected per person.
@peterwhite23 Okay, I tried this on two mainline kernels on Kubuntu 26.04, and I have some news to report. I installed them like this:
sudo add-apt-repository ppa:cappelikan/ppa
sudo apt update
sudo apt install mainline
Then, I used the mainline GUI tool do download and install kernels 7.0 and 7.0.12, but I also had to reinstall the gpu drivers afterwards because the new kernels were missing the nvidia modules.
uname -a:
Linux usertest 7.0.0-070000-generic #202604122140 SMP PREEMPT_DYNAMIC Sun Apr 12 22:05:40 UTC 2026 x86_64 GNU/Linux
Linux usertest 7.0.12-070012-generic #202606091155 SMP PREEMPT_DYNAMIC Tue Jun 9 15:08:35 UTC 2026 x86_64 GNU/Linux
The 7.0 mainline kernel did not solve the issue, the freezes were still happening. But while running the 7.0.12 kernel I am pleased to report that I am no longer able to reproduce the issue. It would seem that updating the kernel did in fact fix the problem. 
So, whatâs the plan now? Wait for Ubuntu to push the 7.0.12 (or 7.1) kernel or should the mainline one be good? I did se a bluetooth driver segfaulting in my syslog on the mainline (not that I need it, but still). While this is technically a (temporary) solution, Iâm gonna leave the thread open for other people that have some findings to report.
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Great detective work, @Plecton.
You could see if itâs already in the proposed pocket, like this user has done; donât do the APT pinning, though, itâs obsolete, so just:
sudo tee /etc/apt/sources.list.d/ubuntu-proposed.sources >/dev/null <<'EOF'
Types: deb
URIs: http://archive.ubuntu.com/ubuntu/
Suites: resolute-proposed
Components: main restricted universe multiverse
Signed-By: /usr/share/keyrings/ubuntu-archive-keyring.gpg
EOF
(courtesy of @minze90)
then sudo apt install --update linux-image-7.0.0-26-generic (do not just upgrade linux-generic, which will make your kernel track proposed; do it manually) and reboot; the NVIDIA modules should build automatically; or just use the *-open variant which should be precompiled and no DKMS neccessary, IIUC â still not an NVIDIA user.
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Unfortunately, I cannot get the thing to work. I installed the 7.0.26-generic kernel like you suggested, but that did not seem to install a working copy of nvidia modules. After booting into 7.0.0.26, I got a basic low-resolution desktop. Even after reinstalling the nvidia driver two times I still cannot get it to run with this kernel.
After booting 7.0.0.26 for the first time I opened the Driver Manager from the âstartâ menu, chose the X.Org driver and applied (this removed the existing nvidia-driver-595-open). After it finished, I selected the nvidia-driver-595-open option from the same window without rebooting and applied the changes. After the changes were applied, I rebooted. It didnât work. Then I tried again by choosing the X.Org driver a second time from the Driver Manager, but this time I fired up a terminal and used âsudo ubuntu-drivers installâ to install nvidia-driver-595-open and rebooted. That didnât help either. Not sure whatâs the deal here.
root@usertest:~# uname -a
Linux usertest 7.0.0-26-generic #26-Ubuntu SMP PREEMPT_DYNAMIC Fri May 29 03:13:00 UTC 2026 x86_64 GNU/Linux
root@usertest:~# ubuntu-drivers=== Welcome to ubuntu-drivers ===
This tool helps you install and manage hardware drivers for your Ubuntu system.â Installed OEM / NVIDIA Drivers â
NVIDIA Drivers:
⢠nvidia-driver-595-openFor more information, use âubuntu-drivers --helpâ or âubuntu-drivers listâ
To install drivers, use âsudo ubuntu-drivers installââ NVIDIA Module Status â
NVIDIA module is not currently loaded
The NVIDIA module should load on next boot
â Next boot module path: /lib/modules/7.0.12-070012-generic/updates/dkms/nvidia.ko.zst
Kernel version difference detected - reboot to use the latest kernel:
Current kernel: 7.0.0-26-generic
Next boot kernel: 7.0.12-070012-generic
(please put such output in preformatted text / code blocks; click </> on an empty line, then paste)
Apparently it gets tripped up by the newer kernel and the currently running one not being that one. Try purging the mainline kernel. Also, sudo apt install --update linux-image-7.0.0-26-generic may only have installed the kernel and not the headers required to build DKMS modules for it; but I was under the impression that the *-open NVIDIA modules are pre-built and thus donât require that step. Perhaps you need the proprietary driver version. Or you may need to install the open modules from proposed as well.
I also think that you might need -t resolute-proposed in the apt command â sorry, my bad. 
sudo apt reinstall -t resolute-proposed --update linux-{image,headers,modules-extra}-7.0.0-26-generic
That should enable APT to pull dependencies from proposed as well, which it canât otherwise, I presume. So try purging the kernel and then run the above and reboot.
You can also have a look at /var/log/apt/history.log and /var/log/apt/term.log to see what happened, when installing the proposed kernel the first time around.
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Hey. I just ended up reinstalling Kubuntu 26.04 afresh. After fully updating it, I enabled the proposed repo same way as before. Then, I installed the 7.0.0-26-generic kernel like so (your âmodules-extraâ package is a 404, by the way):
apt install -t resolute-proposed --update linux-{image,headers,modules}-7.0.0-26-generic
Then I rebooted into it and installed the nvidia drivers. I actually had to install them with apt from command line since the âsudo ubuntu-drivers installâ messed up again and didnât install to the correct kernel. So, it was back to X.Org driver by using the Driver Manager tool to revert, then I fired up a terminal as root:
apt install -t resolute-proposed --update nvidia-driver-595-open
This correctly installed the nvidia open driver for the 7.0.0-26-generic kernel. So, I rebooted and tested. The 7.0.0-22-generic kernel was still showing freezes, but on 7.0.0-26-generic I can no longer reproduce the issue.
Iâm not sure, if this is related or not, but I did notice one other anomaly. This happens on Kubuntu in both kernels (-22 and -26). The screen will sometimes flicker real quick and subtle as if a single frame is being rendered with slightly lower brightness. Either that or something else is dynamically adjusting the brightness of my screen. This is happening on a fresh installation, and I didnât configure anything other than the kernel and the nvidia driver.
Yeah, sorry about that; was going by what my 24.04 installation showed. Apparently there was a change and there is no modules-extra anymore; only linux-main-modules-* for specific purpose, e.g. ZFS.
Ideally, the driver gets installed before the reboot, so as to have everything working.
Without logs we can only guess what went wrong. (If you post log/console output do use pre-formatted text blocks (</>); it looks awful and is hard to read in a quote block with a proportional font and lines wrapped)
Usually that should be what ubuntu-drivers does, but it might not in this case because you did not upgrade the linux-generic metapackage, which was on purpose from my end; otherwise you could end up with your kernel tracking proposed, if you donât take extra measures (see the other thread, if youâre interested in the details).
Is it possible that itâs just the âvisual bellâ in the terminal?
Well, Iâm not crying over what went wrong during driver installation since I managed to get them installed another way, and the bug was confirmed to not be present in 7.0.0-26. Iâll leave it alone for now since it was a temporary installation anyway. The bigger question is what to do next in my primary Kubuntu installation. Just wait until a new kernel is pushed? I guess I could live with that by temporarily switching my refresh rate to 60Hz where the bug is absent. How long does it usually take for a new kernel to be pushed?
And I think the âanomalyâ with the screen flicker might have been my OLED monitorâs automatic brightness adjustment. It seems Firefox momentarily displays a blank white page before loading the proper website content while browsing, and that caused the monitor to automatically adjust the brightness of the rest of the screen for a split second.
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You could just install the proposed kernel and wait until that one trickles down to resolute proper. Bar any pullbacks, by that time the linux-generic package will just depend on the packages youâve installed manually already, so the only thing left to do then, is to mark them as automatically installed:
sudo apt-mark auto linux-{image,headers}-7.0.0-26-generic
(see my posts in the other topic for some elaboration on the why)
I donât know how long that takes, so Iâll âquoteâ the Debian maintainersâ reply on when the next stable is going to be released: âWhen itâs done.â 
You must be sitting in a pretty dark room for the sensor to react to that.
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