mesa update freeze/crash screen before login

[rcornet]

After updating my laptop after a long trip. It starts to bootm, then screen goes black with the mouse pointer hanging over, sddm does not start.

This symptoms I saw them before and were related to mesa libraries. See https://bugs.launchpad.net/ubuntu/+source/sddm/+bug/1909171 for details on that.
But the actual problem seems somewhat different this time.

Furthermore dmesg shows:

[66.441074] QSGRenderThread[1134]: segfault at 39 ip 00007f1ca6c7311b sp 00007f1c98b76630 error 4 in r300_dri.so[7f1ca660b000+10ab000]
[66.441088] Code: b6 40 2d eb ef 66 2e 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 31 f6 e9 95 a2 f9 ff 0f 1f 44 00 00 41 54 48 8d 15 97 b8 b2 00 55 53 <0f> b6 47 39 48 89 f3 48 63 04 82 48 01 d0 3e ff e0 0f 1f 40 00bd

r300_dri.so is from the package libgl1-mesa-dri

I applied the same workaround I did for the previous time that mesa was broken: downgrade to previous mesa version.

I went to Ctrl+Alt-F2, logged in and:
**********
sudo apt install libglapi-mesa=21.0.3-0ubuntu0.3~20.04.5 libglx-mesa0=21.0.3-0ubuntu0.3~20.04.5 libgl1-mesa-dri=21.0.3-0ubuntu0.3~20.04.5 libegl-mesa0=21.0.3-0ubuntu0.3~20.04.5 libgbm1=21.0.3-0ubuntu0.3~20.04.5

sudo apt-mark hold libglapi-mesa=21.0.3-0ubuntu0.3~20.04.5 libglx-mesa0=21.0.3-0ubuntu0.3~20.04.5 libgl1-mesa-dri=21.0.3-0ubuntu0.3~20.04.5 libegl-mesa0=21.0.3-0ubuntu0.3~20.04.5 libgbm1=21.0.3-0ubuntu0.3~20.04.5
***********

Now everything works fine. Other than the mentioned mesa packages everything else is fully updated.

=== In short something got broken again in mesa 21.2.6, downgrading to 21.0.3 fixes the issue. ===

Running Lubuntu 20.04
Kernel:
5.4.0-94-generic #106-Ubuntu SMP Thu Jan 6 23:58:14 UTC 2022 x86_64 x86_64 x86_64 GNU/Linux

lsb_release -rd:
Description: Ubuntu 20.04.3 LTS
Release: 20.04

GPU:
Advanced Micro Devices [AMD/ATI]
RS482M [Mobility Radeon Xpress 200]
driver: radeon

[Timo Aaltonen (tjaalton)]

please try the latest stable release from

https://launchpad.net/~kisak/+archive/ubuntu/kisak-mesa

then at least we'd know if it's fixed in 21.3.x

[rcornet (rcornet)]

I was reticent to install some random ppa. But since compiling it myself would be some adventure. I removed my personal stuff and other data, changed passwords and then installed the kisak ppa.

And it seems to work without issue. Just as well as in 20.04.5.
The current version in the ppa is 21.3.6.
I have no idea what was broken in 21.2.6.
Was there really a need for messing with r300 drivers?

dmesg shows neither errors or weird warnings about mesa.

Everything seems ok.
Only thing I don't know what else might have been installed from that ppa.
Yes I'm a little paranoid.

[Launchpad Janitor (janitor)]

[Expired for mesa (Ubuntu) because there has been no activity for 60 days.]