Description
On fresh body nodes using the MTT Virtual Display Driver (IDD framework), hydrabody writes vdd_settings.xml with portrait resolutions but does NOT run VDD Control.exe after writing it. The IDD driver only registers new modes when VDD Control.exe communicates with the Virtual Desktop Service in the interactive user session.
As a result, SetDisplayConfig returns ERROR_GEN_FAILURE (0x1F) when Sunshine tries to apply portrait resolution because the mode is not in the IDD-registered mode list.
Root cause: hydrabody calls device bounce (Disable/Enable-PnpDevice) after writing vdd_settings.xml. For MTT VDD (IDD model) this is insufficient -- the IDD driver ignores vdd_settings.xml changes until VDD Control.exe applies them via the Virtual Desktop Service.
Fix: after device bounce, also launch VDD Control.exe in interactive session via Register-ScheduledTask with Interactive logon (same pattern as set_vdd_primary2.ps1). Run once, wait for completion, then delete the task.
Confirmed on chunky-turnip-23 (node-b961f1c8), RTX 5070 Ti, hydrabody v2.0.43, orientation-switching testbook 2026-05-20.