https://bugs.kde.org/show_bug.cgi?id=525746
Rikard Nyquist <[email protected]> changed: What |Removed |Added ---------------------------------------------------------------------------- Status|REPORTED |CONFIRMED Ever confirmed|0 |1 --- Comment #10 from Rikard Nyquist <[email protected]> --- I had an issue with the cpu usage and my AI came to the conclusion that this bug might be what is causing it. This is the last response I got, it might help or not: " I can reproduce this on Fedora 44 with plasma-workspace 6.7.5 / kwin 6.7.5 (Wayland session, AMD GPU), with the same "There are no outputs - creating placeholder screen" flood in the journal when the TV (connected via HDMI) is switched off and all other outputs are gone. I captured profiling data during an attack: plasmashell (~90-100% CPU): perf shows the Mesa GL thread (plasmashel:gl0) stuck in a loop: glthread_unmarshal_batch → st_Clear → st_update_framebuffer_state → dri_st_framebuffer_validate → update_buffers_if_needed → wl_display_roundtrip_queue → wl_display_dispatch_queue (~40% of samples in this path) kwin_wayland (~60% CPU): main thread busy in the event loop — perf shows qt_safe_poll/ppoll/sock_poll/unix_poll/__pollwait dominating, i.e. it's drowning in socket traffic rather than computing. strace counts during an attack (~10 s): kwin_wayland: 4,772,319 recvmsg / 2,387,075 sendmsg (with 2,386,155 EAGAIN recvmsg) plasmashell: 505,038 recvmsg / 252,519 sendmsg (252,519 EAGAIN) i.e. the plasma GL thread is doing tens of thousands of wl_display_roundtrips per second against kwin while no real outputs exist. Journal at attack start: every KDE client logs "There are no outputs - creating placeholder screen" at the same second, plasmashell logs "requesting unexisting screen available rect -1", and the HDMI audio sink disappears. systemctl --user restart plasma-plasmashell.service stops it temporarily, as others have reported. Happy to provide the full perf reports or perf.data if useful. " -- You are receiving this mail because: You are watching all bug changes.
