This is probably a proprietary nvidia driver related issue - but I’ll raise it here in case anyone else has an answer or trips over the same issue.
After upgrading to 12.3 there are small black dots at the top left that come and go when moving windows around (KDE desktop). Looks like the problem reported here:
As reported in the referenced post, switching to a text console and back fixes the issue.
Other relevant facts that may be contributing:
I upgraded 12.2 to 12.3 using zypper dup, but also added the 12.3 DVD as a higher priority repo than the net repos.
Initially I had no X because the nvidia driver didn’t seem to correctly update from nvidia’s site. Seems like I had two versions installed (old and new). I used text console yast2 and deleted the old driver and reinstalled the 310 driver and that got me going.
My boot screen splash is listing 12.3 with the dark theme (not to my tastes), but the boot menu lists all 12.2 entries that really boot to 12.3. So maybe my boot splash and menu is not as it should be.
Correct, followed the recommended procedure and had no 12.2 repos active. But did use the 12.3 DVD as a higher priority repo than the network repos.
On picking the 12.2 it does boot 12.3 kernel-desktop-3.7.10 - so I suspect the menu text is wrong rather than something more serious. I have yet to get my head around the grub2 boot loader changes, but I guess I will have to sort this out at some point. I noticed that yast2 reports the boot loader as being installed in root, so perhaps I have some kind of indirect bootloader setup.
That should only make a difference in download time. The packages in the distribution repos are exactly the same as the ones on the DVD. The repos have more packages even, due to the limited size of a DVD iso.
I found the reason of the artifacts: it is plymouth graphical bootsplash. Artifacts are visible when plymouthd doesn’t clear video memory after exit. Plymouth store video memory contents if for quit init.d plymouth script uses --retain-splash option. I removed this option, but bug still exist. In my situation plymouthd was in hang or crash state when init.d script send quit command before X start so it can’t do deinitialize sequence and it cause problems with nvidia driver.
I have since resolved the misleading bootloader menu entry - it was not really important. It seems that the 12.2 upgrade put GRUB_DISTRIBUTOR=“openSUSE 12.2” in /etc/default/grub. The 12.3 update did not update this setting. Looking at a fresh 12.3 install running in a VirtualBox, the fresh 12.3 sets GRUB_DISTRIBUTOR=“openSUSE”. So that explains it. I changed the grub.cfg value and I also had to reset the default by using the grub2-set-default command (default is written to /boot/grub2/grubenv).
vi /boot/grub2/grub.cfg
grub2-mkconfig -o /boot/grub2/grub.cfg
grub2-set-default openSUSE
It looks like Yast2 bootloader tool could be used to fix this, it has these settings listed, but I went the command line route.