Description of problem: Since the recent upgrade of Qt to 5.12.1, Plasma fails to start on my machine with NVIDIA graphics (old model, NVIDIA Corporation GF119 [GeForce GT 610] (rev a1). Maybe Qt is not at fault, and it just uncovered some bug in Nouveau. For now, I'm setting this to Qt core. Downgrading all Nouveau-related packages I could didn't help. Some Archlinux users are also experiencing this, or similar: https://bbs.archlinux.org/viewtopic.php?id=243962 + https://bbs.archlinux.org/viewtopic.php?id=243962 And there's a related issue opened against Nouveau: https://bugs.freedesktop.org/show_bug.cgi?id=109556 For anyone else in a similar situation: For now, my workaround has been disabling KWin's compositing, renaming the plasmashell binary to prevent it from crashing the whole OS, and launching Tint2 to have a decent task manager in the absence of Plasma's panels. I initially had a pretty stable system with the compositing on, but eventually some of the alt-tab popups ended up freezing the thing. Without plasmashell and without compositing, it seems quite stable, so far. What also worked, but was quite horrible, was setting "NoAccel" "true" in the device section of xorg.conf. Version-Release number of selected component (if applicable): Version : 5.12.1 Release : 1.mga7 How reproducible: Always. The level of "frozenness" varies, sometimes the initial steps of a REISUB can get you back to the login screen, but often you need the whole REISUB to reboot. Steps to Reproduce: 1. Set your system to use the Nouveau driver for your NVIDIA card. 2. Log into Plasma Desktop.
Created attachment 10732 [details] dmesg output of one instance where the freeze was not absolute
CC: (none) => jan-bugs
I pasted a link twice there. It was supposed to be: https://bugs.archlinux.org/task/61638
Another fd.o report: https://bugs.freedesktop.org/show_bug.cgi?id=109558
CC: (none) => mageiaSee Also: (none) => https://bugs.mageia.org/show_bug.cgi?id=24060
CC: (none) => marja11Assignee: bugsquad => kde
Users in Archlinux's bug report seem to be mixing two different issues, but in any case, point to a bugreport to Qt that seems interesting, with a possible patch: https://bugreports.qt.io/browse/QTBUG-73691 From what I can understand, the problem might be with whitelisting the use of multithreading in more situations. I remember QWebEngine having serious problems with Nouveau due to exactly that, multithreading issues.
Please test next qtbase5
CC: (none) => mageia
(In reply to Nicolas Lécureuil from comment #5) > Please test next qtbase5 FWIW Nicolas, just got that update, and early indications are that it has fixed the flickering that's been seen with the Intel i915 driver, Bug 24060. Will try nouveau on my old nvidia Geforce 9800GT tomorrow.
CC: (none) => andrewsfarm
(In reply to Nicolas Lécureuil from comment #5) > Please test next qtbase5 Thanks! I'll test this as soon as I can reboot, hopefully tonight =)
I have now tested with nouveau, and from what I've seen so far Plasma is now the most stable with nouveau that I have seen so far - and that includes all of Mageia 6. BTW, I made sure that nouveau and OpenGL 2.0 were both being used. Makes me really wonder if some of the older nvidia hardware, those no longer supported with proprietary drivers, would now work with Plasma.
Tried now on a machine using a Geforce 210 card. First boot after getting many updates was using Xrender as compositor. That was stable. Another boot after switching to OpenGL 2.0 had a few glitches (Jittery scrolling using mouse wheel in Firefox, flashing when the logout screen appeared), but did not freeze. Auto-login is active on these systems. The second and subsequent boots show a momentary (1-2 seconds) video glitch (a "scrambling" is how I would describe it) when the sddm video first shows, but corrects and is very stable after that, including when shutting down. Checking the 9800GT system again shows the same momentary glitch and subsequent stability. While not quite as perfect as I thought it was when I typed Comment 8, it is definitely now usable.
(In reply to Nicolas Lécureuil from comment #5) > Please test next qtbase5 PER-FECT! Thanks! All issues, gone =) Perfectly running Plasma, with smooth compositing and everything, no flickering, no issues at all (so far, at least, after one hour). Although, contrary to some other people, I had no flickering at all before the "Qt 5.12.1 disaster", either. I'll report again after more hours of use. Cheers! o/
So ~24h later, all's still good! \o/
Several months later, I think this can, quite safely, be closed =)
So closing this bug!
Resolution: (none) => FIXEDCC: (none) => geiger.david68210Status: NEW => RESOLVED