https://bugs.kde.org/show_bug.cgi?id=525537
--- Comment #8 from [email protected] --- Captured a WAYLAND_DEBUG=1 trace of plasmashell across a suspend/resume cycle. The trace contains both the healthy and the bad state, and the difference is unambiguous. The affected surface is wl_surface#55, created as a layer-shell surface with namespace "desktop" (zwlr_layer_shell_v1.get_layer_surface(..., "desktop")) — i.e. the wallpaper/desktop layer. Before suspend: 7 commits on that surface (static wallpaper, as expected). After resume: 4,305 commits total, at a sustained ~119 commits/sec on a 120 Hz panel, indefinitely, with no content change on screen. In an 8,000-line slice of the bad state (6.71s): 799 REQ wl_surface#55.frame 799 REQ wl_surface#55.damage_buffer 799 REQ wl_surface#55.commit 799 REQ wl_surface#55.attach 799 EVT wl_callback#106.done 798 REQ wl_display#1.sync Every frame does a full attach + damage_buffer + frame + commit with a real buffer (three wl_buffers rotating, normal releases), so it is genuinely re-rendering identical content each refresh. Notably there is also one wl_display.sync roundtrip per frame; at the syscall level that roundtrip returns the same serial (0x3899) every time. The commits are issued from the {mesa egl surface queue} thread rather than the default queue. perf record during an episode shows the Wayland event thread dominating (~66% of P-core samples in kernel, plus libc/libwayland), with QSGRenderThread in libgallium on the E-cores. strace -c over 10s in the bad state: 35,017 futex, 15,718 ioctl, 7,076 poll, 4,800 recvmsg (2,400 EAGAIN), 4,800 getpid — far above the ~120/s a 120 Hz frame loop would need. The surface also has a wp_fractional_scale_v1 attached, and kwin sends preferred_buffer_scale(2); changing the output scale from 1.7 to 1.6 did not affect the bug, but noting it in case the fractional-scale path is involved. Correction to my earlier reports: the episode is not permanent. It does end on its own after some minutes, though I have not yet timed it precisely. Restarting plasmashell also ends it immediately. Also ruled out since my last comment: fingerprint unlock (deleted all enrolled prints — the spurious wake-time auth attempt and this bug both still occur), night light/HDR/VRR (all at defaults, nothing in kwinrc), multiple Activities (only one). Kernel is now 7.2.6 (was 7.2.2 when filed) — unchanged behavior across both. Full trace available on request. -- You are receiving this mail because: You are watching all bug changes.
