User's insight, and it fits the evidence exactly: in duplicate_output the FIRST
DuplicateOutput1 (called microseconds after the caller releases the old
duplication via self.dupl=None) returns E_ACCESSDENIED, but the legacy
DuplicateOutput a beat later SUCCEEDS — the only difference is TIMING. The
kernel-side teardown of the just-released duplication is async, so the immediate
DuplicateOutput1 races it ('output still duplicated' -> E_ACCESSDENIED). We then
fell straight through to legacy DuplicateOutput, which 'succeeds' into a FRAGILE
dup that churns ACCESS_LOST/MODE_CHANGE every few ms on this cross-GPU IDD
(causing the post-login freeze + UAC-confirm drop).
Fix: retry DuplicateOutput1 up to 5x with escalating 2/4/8/16 ms waits before
falling back to legacy, so the teardown finishes and the ROBUST DuplicateOutput1
dup succeeds (no churn). Bounded (~30 ms worst case) so a genuine failure still
falls back quickly. This is exactly Apollo's 2x/200ms retry rationale.
Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
enricobuehler
eb451d8bc6