enricobuehlerandClaude Fable 5 cca5008805 feat(host,web): experimental DDC/CI monitor power-off for Exclusive sessions ...

The sole-virtual-display stutter investigation's active experiment: when the
Exclusive isolate deactivates a physical monitor, the dark-but-connected head
keeps getting serviced (monitor standby auto-input-scan / DP link churn) at a
seconds-scale cadence — the leading suspect for the periodic double-jolt. A
panel commanded off over DDC/CI (the VESA monitor-control channel in the video
cable) believes it has an owner and, on cooperating firmware, stops probing.

- New `ddc_power_off` display-policy axis (default off): orthogonal to presets
  like game_session, stored in display-settings.json, surfaced in GET/PUT
  /display/settings + the enforced list, carried through the layout transform.
- windows/ddc.rs: VCP 0xD6 power-mode control via the dxva2 Physical Monitor
  API. Deliberately DPMS-off (0x04, DDC stays responsive, signal return wakes)
  and never power-button-off (0x05, bricks-until-button on many monitors).
  Probe-before-write; every failure is skip-and-log — monitors without DDC/CI,
  OSD-disabled, or behind docks/KVMs degrade to a logged no-op.
- Manager wiring: panels commanded off immediately BEFORE the Exclusive CCD
  isolate (an HMONITOR — and with it the DDC channel — only exists while the
  display is active); teardown wakes them right after the CCD restore, where
  returning signal alone already wakes most firmware.
- Web console: an Experimental-badged on/off control on the display card,
  applied immediately like the game-session axis and preserved across preset
  switches; EN/DE strings incl. the wake-failure escape hatch (press the
  monitor's power button once, turn the option off).

Diagnostic value on top of the fix: if this kills a reporter's stutter, the
churn is monitor-firmware-initiated; if only topology=primary/extend does, the
driver services dark heads regardless — the two remaining root-cause classes.

Verified: Linux 258 tests + clippy + fmt clean; Windows (RTX box) 220/220 +
clippy clean; web tsc + production build clean; openapi.json regenerated.

Co-Authored-By: Claude Fable 5 <noreply@anthropic.com>

2026-07-10 12:32:36 +02:00

..

openapi.json

feat(host,web): experimental DDC/CI monitor power-off for Exclusive sessions

2026-07-10 12:32:36 +02:00