kernel 5.8.0-50-generic causing display scramble

[JamButty]

After I updated to kernel 5.8.0-50-generic, I started getting severely scrambled displays - missing parts, corrupted text, strobing, blank lines - the works. It was the same for all applications. Then I booted into Windows and found no trace of it. Then I booted into the prior kernel, 5.8.0-49-generic, and again, no problems. I can use that for now, but as soon as the next kernel loads, 5.8.0-49-generic will not be available, at least not directly from the boot menu.

Anyone else having similar issues?

[CatKiller]

I've not experienced the issue, but

I can use that for now, but as soon as the next kernel loads, 5.8.0-49-generic will not be available, at least not directly from the boot menu.

this isn't strictly true. The number of old kernels to keep is a configurable parameter (although I don't know off hand where it's configured), and (temporarily) removing the HWE metapackage will stop you getting any new kernels at all until you know that the bug has been fixed. You should file a bug report, if there isn't one already, detailing the regression. Alternatively, you could go the other way, and try a much newer kernel from the mainline repository to see if the issue has been fixed.

[ajgreeny]

Do you have secure boot enabled?
Are you using an nvidia graphics card which needs a driver installed for the new kernel?

If so disable secure boot, install the nvidia driver needed and try again. Unfortunately Windows updates can, I gather, re-enable secure boot even if you have disabled it in the past, stopping the necessary modules for the driver being installed properly.

[JamButty]

Thankfully, Ubuntu is not paternalistic like ******* which shoves updates down your throat with or against your will. I can just decline updates for a while until I see if this is fixed. I seem to remember a few years ago that several ( maybe 5 or 6) kernels used to be offered in the default boot menu.
I found a couple of pages sort of related, but they explain how to set an old kernel as the default, rather than how to expand the menu choices. Also there are very many articles explaining how to get rid of excess menu choices, so this must have been a problem in the past.
I get contradictory info on what kernels are available to me.
One command lists about 22 kernels:

sudo dpkg -l | grep linux-image

but another indicates there are only two in BOOT

ls /boot/

[JamButty]

ajgreeny - Secure boot IS disabled
gpu is onboard (Xeon E3-1200 v3/4th Gen Core Processor Integrated Graphics Controller)
Previously, I have never had to dl drivers specific to this.

[CatKiller]

Also there are very many articles explaining how to get rid of excess menu choices, so this must have been a problem in the past.

It was. A few releases ago the defaults were to have a smallish EFI partition and to never autoremove kernel packages. Unsurprisingly, as time went on, there were a lot of people with broken systems: the kernel installation couldn't finish because there was no space, so package management was broken, and, in some cases, you couldn't boot because the kernel hadn't finished installing. Nasty. So some versions are kept, but old ones are autoremoved, now.

[CelticWarrior]

...a smallish EFI partition

I think you mean a smallish /boot partition. The ESP stores .efi files, not kernels.

[CatKiller]

I think you mean a smallish /boot partition. The ESP stores .efi files, not kernels.

Could be. I wasn't affected by it (habitually tidying old kernels after I'd checked the new one works), I just saw the people having the issue in the forum.

[CelticWarrior]

With LVM+LUKS the installer typically creates a separated /boot partition and the default size used to be very small indeed.
Normal installations do not have that problem.

[grahammechanical]

I can use that for now, but as soon as the next kernel loads, 5.8.0-49-generic will not be available, at least not directly from the boot menu.

Do not use Software Updater for the time being. Use the terminal.

sudo apt update
sudo apt upgrade

When you have confirmed that that any new kernel does not cause problems, then you can run Software Updater and it will want to remove any old kernels. I would wait until at least two new kernels are confirmed as acceptable. Then both the good, older 5.8 kernel and the later, bad 5.8 kernel can be removed.

Regards