Intermittent UI freezes since LTS HWE linux 6.5.0-18

[Dennis Gnad]

When running the HWE kernel linux-6.5.0-18 and newer in Ubuntu 22.04.4 LTS ( 6.5.0-18.18~22.04.1 ), I get intermittent freezes of about 1-5 seconds of the whole UI (even the mouse pointer stops moving). Sound continues to work. There is absolutely nothing logged in the kernel or any other system logs.

I downgraded the kernel in a current up-to-date Ubuntu 22.04.4, and it's running perfectly fine with linux-image-6.5.0-17-generic ( 6.5.0-17.17~22.04.1 ).

As intuition I suspect amdgpu or its interaction with firmware, since there is nothing logged in the kernel and its a graphical issue. I couldn't find the patch log of the ubuntu kernel, but vanilla 6.5.17 to 6.5.18 has some amdgpu patches which I guess might be involved, if ubuntu 6.5.0-17 to 6.5.0-18 has anything to do with those vanilla kernel versions.

I am attaching the two files (version.log and lspci-vnvn.log called no-freezes_version.log and no-freezes_lspci-vnvn.log) when no freezes happen (kernel 6.5.0-17) and lspci-vnvn.log and version.log when they happen.

The generic non-hwe kernel 5.15 is no option - that one freezes the entire system as soon as the screen goes to power-saving mode, see my previous (confirmed) bug: https://bugs.launchpad.net/ubuntu/+source/linux-hwe-5.15/+bug/1987413

1)

> lsb_release -rd
Description: Ubuntu 22.04.4 LTS
Release: 22.04

2) linux-generic-hwe-22.04: Installed: 6.5.0.21.21~22.04.11

3) No freezes

4) Intermittent UI freezes of 1-5 seconds including mouse pointer when starting multimedia applications, looking at images, etc. But no audio freezes or anything. Nothing logged in system or kernel logs when it happens.

The freeze typically happens (but might not be always like that), for instance when starting a new youtube video in firefox or chrome, but subsequent ones work fine for a while. However, it might also happen when looking at a newly received image in any messenger app, it is not exclusive to firefox, or youtube, or videos.

[Dennis Gnad (bluesceada-1)]

Additional info and observations:

 - Sometimes there is also flickering in videos (for example zoom calls), without freezing

 - The flickering and freezes seem to be less (but not entirely removed!) when using a lower refresh rate

 - While I am using the mouse, no flickering will occur, as soon as I stop moving, it will sometimes flicker - freezing seems to be able to happen while moving the mouse

 - The used screen is a 144 Hz screen with support for AMD FreeSync, including the AMD Radeon RX 6600 XT GPU in the system. The screen is also connected with Displayport as supposed to be for FreeSync. In a dual-booted Windows, FreeSync is automatically activated and seems to work, and there are no freezes. - I am not sure how to check if FreeSync is enabled/used in Ubuntu.

[Dennis Gnad (bluesceada-1)]

Since the situation was unbearable, as I didn't want to sit with a kernel that had no recent security updates, I made the jump to 24.04 (beta), everything is running fine now.

Some extra info about my hardware: MSI B450M GAMING PLUS (MS-7B87) Mainboard with recent Bios / AMD Ryzen 5 5500 / RAM: Corsair Vengeance LPX 32GB DDR4-3600 / MSI AMD Radeon RX 6600 XT