SUMMARY I've been using the X11 session for the last few hours because I'm trying to solve a different bug. Almost as soon as I did so, I noticed the first time my screen went to sleep that my laptop's fan went crazy and it started heating up significantly. Since then I've been trying to work out the cause, and it appears to be KWin trying and failing to do something repeatedly with the screen (or screens) that aren't on. Since I've been working on the problem, my screen has been off for only brief intervals for testing, and yet in only 3 hours the following has been printed to my system log 11,183,200 (!) times: kwin_x11[24922]: qt.gui.icc: fromIccProfile: failed size sanity 2 STEPS TO REPRODUCE Note that I haven't confirmed that all these steps are necessary for reproducing the issue. 1. Use the Plasma X11 session. 2. Have an external screen attached and Plasma set to display only on the external screen. The laptop lid is closed. 3. Have an ICC color profile that you've made for the screen with DisplayCal set for the screen in colord. 4. Allow the screen to turn off automatically. OBSERVED RESULT The log is spammed with the message shown above, system activity increases - I'm not sure yet whether the log spam is a symptom of the system problem, or if the system problem is a symptom of the log spam. EXPECTED RESULT No log spam, laptop stays cool, fans stay silent. SOFTWARE/OS VERSIONS Operating System: Arch Linux KDE Plasma Version: 5.93.0 KDE Frameworks Version: 5.249.0 Qt Version: 6.7.0 Kernel Version: 6.7.3-arch1-1 (64-bit) Graphics Platform: X11
kwin has no code that loads ICC profile or uses QColorSpace::fromIccProfile(), it's done by Qt. It might be an issue in QtXCB QPA plugin. Can you please file a Qt bug report and then leave a link here?
> kwin has no code that loads ICC profile That's at least a little surprising, given that the compositor now handles profiled screen corrections under Wayland. I do have a profile set (visible in Wayland) in the "Color Profile" field of Display Configuration (under System Settings). I was wondering if this could be making the X11 session unhappy somehow. > Can you please file a Qt bug report and then leave a link here? The warning it generates is something I've seen from nearly every Qt application for years and years, unfortunately. They appear to have a sanity check on the size of ICC profiles that basically every DisplayCAL created profile violates because of the embedded LUT. As it doesn't seem to interfere with the operation of my system, I've been ignoring it. In my system log from the last 3 days, I see the message at least once from all of the following programs: ark, dolphin, gmenudbusmenuproxy, gwenview, kaccess, kactivitymanagerd, kdeconnectd, kded6, kde-open, kioexec, kioworker, konsole, krunner, kscreen_backend_launcher, kscreenlocker_greet, ksmserver, ksmserver-logout-greeter, kwalletd6, kwin_x11, kwrite, okular, org_kde_powerdevil, plasmashell, polkit-kde-authentication-agent-1, spectacle, systemsettings, xdg-desktop-portal-kde, xembedsniproxy I will do my best to report the issue to Qt, if you think it's necessary and can point out the appropriate component to file the bug against. *However*, my concern here is specifically with the log spam. I've never seen Qt do this before, and so I'm thinking kwin_x11 is probably attempting (and failing) to do something repeatedly with my screen off, which is resulting in the log entry. The system resource consumption and overheating could be downstream of the log issue, or it could be downstream of whatever it is that kwin_x11 is doing.
To clarify, kwin_x11 has no code that loads an ICC profile. Only the output configuration part of kwin_wayland does that, and it doesn't use Qt to do it.
Adding the x11-only keyword