EPOLLET reported a descriptor again only after a scan had seen it not
ready. Xorg watches its clients edge-triggered; when it read part of a
client's requests and more arrived before its next scan, the socket never
looked not-ready, so it was never reported again -- X waiting on the
client, the client waiting on X. One CPU almost never hit it; on a 16-thread
laptop the desktop froze within seconds: Window Maker's menu stuck, xterm
never mapped, text gone, and Caps Lock dead because X owns the LED.
Now a still-ready descriptor is reported again whenever anything has
signalled readiness since its last report (poll_generation()), which may be
spurious, as EPOLLET permits, and is never missed. Reproduced and verified
with QEMU at -smp 8: the root menu works and xterm runs cmatrix.
Co-Authored-By: Claude Opus 5.5 <noreply@anthropic.com>
Claude-Session: https://claude.ai/code/session_01S1giNvrHTrPMPw7V6x1kQ4
4743df8c4a