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fix(host): preserve a physical monitor's refresh when adding a virtual display

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Connecting reset an existing physical monitor's refresh (e.g. 120->60 Hz)
because the topology code read the physical's mode AFTER the virtual output
perturbed the compositor layout — by which point it had already been
downgraded. Read/preserve each physical's mode from a pre-connect snapshot.

- Mutter: build_primary_keeping_physicals takes the pre-virtual snapshot and
  preserves each physical's real mode (pick_keep_mode, unit-tested)
- KWin: capture each output's mode when disabling for exclusive, re-assert it
  on re-enable (a bare enable defaulted to ~60 Hz)
- Windows: skip the refresh-resetting SDC_TOPOLOGY_EXTEND when a physical is
  already active

Co-Authored-By: Claude Opus 4.8 <noreply@anthropic.com>
This commit is contained in:
Enrico Bühler
2026-07-06 10:33:30 +00:00
parent 79c4f4cbc1
commit 7257bcb6a6
4 changed files with 269 additions and 37 deletions
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crates/punktfunk-host/src/vdisplay/windows/manager.rs
+28 -12
View File
@@ -33,8 +33,8 @@ use windows::Win32::System::Threading::{
use super::{DisplayOwnership, Mode, VirtualOutput};
use crate::win_display::{
force_extend_topology, isolate_displays_ccd, resolve_gdi_name, restore_displays_ccd,
set_active_mode, set_virtual_primary_ccd, SavedConfig,
count_other_active, force_extend_topology, isolate_displays_ccd, resolve_gdi_name,
restore_displays_ccd, set_active_mode, set_virtual_primary_ccd, SavedConfig,
};
/// The per-backend REMOVE key the driver stamps on ADD and consumes on REMOVE. SudoVDA keys monitors by
@@ -673,16 +673,32 @@ impl VirtualDisplayManager {
ccd_saved = unsafe { isolate_displays_ccd(added.target_id) };
}
Topology::Primary => {
// The IDD auto-activates as the SOLE display on a headless box, so the
// physical (if present) is deactivated and QueryDisplayConfig sees only the
// virtual. Force EXTEND first to (re)activate every CONNECTED display
// alongside the virtual, THEN reposition to make the virtual primary — so the
// physical stays active. (The bring-up above only force-EXTENDs when the
// virtual FAILS to auto-resolve; here it resolved, so we do it explicitly.)
// SAFETY: `force_extend_topology` drives the CCD topology FFI (no args, no borrowed
// memory), under the `state` lock — the sole topology mutator.
unsafe { force_extend_topology() };
thread::sleep(Duration::from_millis(300));
// On a headless box the IDD auto-activates as the SOLE display, so a physical
// (if present) is deactivated and QueryDisplayConfig sees only the virtual —
// force EXTEND to (re)activate every connected display alongside the virtual,
// THEN reposition to make the virtual primary. BUT on a box whose physical is
// ALREADY active (the IDD came up extended beside it — the common desktop case),
// that physical is already lit at its real mode; re-applying the bare
// `SDC_TOPOLOGY_EXTEND` preset would only re-pull each display's mode from the
// persistence DB, RESETTING a 120 Hz panel to 60 Hz. So force-EXTEND only when the
// virtual is currently sole; otherwise skip straight to the reposition, which
// re-supplies each physical's QUERIED mode verbatim (preserving its refresh).
// SAFETY: `count_other_active` runs the CCD QueryDisplayConfig FFI (Copy target id
// by value, owned result), under the `state` lock.
let already_extended =
unsafe { count_other_active(added.target_id) }.unwrap_or(0) > 0;
if already_extended {
tracing::info!(
"display topology=primary — a physical display is already active; \
skipping force-EXTEND (preserves its refresh) before making the \
virtual primary"
);
} else {
// SAFETY: `force_extend_topology` drives the CCD topology FFI (no args, no
// borrowed memory), under the `state` lock — the sole topology mutator.
unsafe { force_extend_topology() };
thread::sleep(Duration::from_millis(300));
}
// SAFETY: `set_virtual_primary_ccd` takes the `Copy` target id by value and returns
// an owned `SavedConfig` (no borrowed memory crosses), under the `state` lock.
ccd_saved = unsafe { set_virtual_primary_ccd(added.target_id) };