At first I thought to get 21.04 I needed to install it and did so. Later I was introduced to Mainline. There I was able to try a kernel and not actually install it so I could easily roll back.

Do you think I could do this with the 21.10 kernel?

Before next Thursday I don't know, but then I have to think yes.

I gave it a try and it worked fine for the game I play. I used to stream, now I don't.

I will check out the dual screens later today.

It that works I need to decide, if/when to upgrade to 21.10

Well, it is great to get my game running and save money but, dual screens is not supported, not even when the additional screen is turned off. The actual HDMI cable needs to be removed.

If the cable is not removed grub comes up with a number of errors and then hangs meaning a hard reboot is needed.

I do need two screens but if I upgrade to 21.10, support is only for 9 months. However, I can't wait until 22.04 LTS is released in 2022 so must take a chance as I may not be around then.

Have you any advice on upgrading via distupgrade v fresh install?

I have more than 20 *buntu installations. It's been about 4 years since the last time I did a fresh *buntu installation on any of my own PCs, because that PC was new. Upgrades work for me just fine.

Thank you.

This behavior was initially reported in the DRM bug tracker several months ago. A fix (actually a kernel workaround, for a defective PC BIOS) was just announced on Monday here.

What model Asus motherboard is this CPU in?

TUF gaming Z590-PLUS WIFI

"Apparently contains the fix for Tumbleweed. My Asus B560M"

I await your reply to your mobo query before attempting this.

Please bear in mind that since this thread was started I now have a dedicated GeForce RTX 3060 gfx card and because of the failings to retain the settings for the card I have switched to windows where it works fine for gaming. In linux it remembers nothing and that does not matter when I am not gaming. I will wait for the next LTS to see if it gets fixed.

That being so, I don't have any problem now because both screens are permanently connected and the second screen is off in the majority of cases of use in linux.

Thank you for your assistance.

That model was reported to have the problem in September in https://gitlab.freedesktop.org/drm/intel/-/issues/4150, which was marked as a duplicate of https://gitlab.freedesktop.org/drm/intel/-/issues/4762, the report I filed and which was marked fixed.

Based upon kernel developer comments in the openSUSE bug that I reported about multi-display lockups on Rocket Lake, it would not surprise me if 22.04 is officially released without the fix. The current kernel in 22.04 is 5.15, which is an LTS release. The fix seems headed upstream only to 5.17, which is @RC3 now. Hopefully it will find its way into the 5.15 LTS 22.04 ships with as well.

Thank you for thank info.