https://bugs.freedesktop.org/show_bug.cgi?id=100465
--- Comment #24 from Zachary Michaels zmichaels@oblong.com --- Hi! There is a stress test here that we have been using to reproduce this issue: https://github.com/Oblong/thrasher
Enabling debug tracing works around the issue. Specifically, when si_draw_vbo calls si_trace_emit, the problem goes away.