unom/punktfunk
1
0
Fork 0
Code Issues Pull Requests Actions Packages Projects Releases 14 Wiki Activity

feat(vdisplay/mutter): pin the client's refresh by default; drop PUNKTFUNK_MUTTER_VIRTUAL_REFRESH

Browse Source 
The >60 Hz virtual-monitor path (RecordVirtual "modes" with the client's exact WxH@Hz)
was gated behind PUNKTFUNK_MUTTER_VIRTUAL_REFRESH, default OFF, after a high-refresh
virtual CRTC SIGSEGV'd gnome-shell on session teardown. That crash was since fixed by
stopping the screencast before any monitor reconfig, so the gate is dead weight — and a
silent footgun: every non-headless GNOME client was capped at Mutter's PipeWire-derived
60 Hz unless they knew the hidden flag.

Make it the default: the custom-mode path now runs whenever mode.refresh_hz > 60 (≤60 Hz
stays byte-identical to before — Mutter's 60 Hz default is already correct), and the
virtual_refresh_enabled() env read is removed. Docs updated (configuration.md env table,
vrr-plan.md reference).

Co-Authored-By: Claude Opus 4.8 (1M context) <noreply@anthropic.com>
This commit is contained in:
Enrico Bühler
2026-07-05 19:25:36 +00:00
parent 74c9e46faf
commit aa012c6b45
3 changed files with 10 additions and 26 deletions
Download Patch File Download Diff File Expand all files Collapse all files
crates/punktfunk-host/src/vdisplay/linux/mutter.rs
+8 -23
View File
@@ -285,15 +285,16 @@ async fn connect(mode: Mode) -> Result<MutterSession> {
)
.await?;
// 3. The virtual monitor. By DEFAULT we let Mutter derive the refresh from the PipeWire
// framerate (it defaults the virtual monitor to 60 Hz) — universally safe.
// PUNKTFUNK_MUTTER_VIRTUAL_REFRESH=1 pins the client's exact WxH@Hz via RecordVirtual's "modes"
// (explicit size + refresh-rate; Mutter ≥ 47) for true >60 Hz — validated at 5120×1440@240 on
// Mutter 50 + NVIDIA. (A high-refresh virtual CRTC used to SIGSEGV gnome-shell on teardown; the
// stop-screencast-before-any-monitor-reconfig teardown below avoids that.)
// 3. The virtual monitor. For >60 Hz we pin the client's exact WxH@Hz via RecordVirtual's
// "modes" (explicit size + refresh-rate; Mutter ≥ 47) — validated at 5120×1440@240 on Mutter 50
// + NVIDIA. At ≤60 Hz we let Mutter derive the refresh from the PipeWire framerate (its 60 Hz
// default is already correct), so the custom-mode path only runs when it buys something.
// (A high-refresh virtual CRTC used to SIGSEGV gnome-shell on teardown, which is why this was
// once gated behind PUNKTFUNK_MUTTER_VIRTUAL_REFRESH; the stop-screencast-before-any-monitor-
// reconfig teardown below fixed the crash, so pinning the client's refresh is now the default.)
let mut rec: HashMap<&str, Value> = HashMap::new();
rec.insert("cursor-mode", Value::from(CURSOR_EMBEDDED));
if virtual_refresh_enabled() && mode.refresh_hz > 60 {
if mode.refresh_hz > 60 {
let mut vmode: HashMap<&str, Value> = HashMap::new();
vmode.insert("size", Value::from((mode.width, mode.height)));
vmode.insert("refresh-rate", Value::from(mode.refresh_hz as f64));
@@ -382,22 +383,6 @@ type CurrentState = (
type ApplyMon = (String, String, HashMap<String, Value<'static>>); // connector, mode_id, props
type ApplyLogical = (i32, i32, f64, u32, bool, Vec<ApplyMon>);
/// Opt-in: pin the virtual output to the client's exact refresh via RecordVirtual "modes" (true
/// above-60 Hz). Off by default — Mutter-derived 60 Hz is safe on every host; high-refresh virtual
/// CRTCs are validated on Mutter 50 + NVIDIA but behaviour can vary, so it stays opt-in. (The
/// teardown SIGSEGV that first motivated this gate is fixed by stopping the screencast before any
/// monitor-config change.)
fn virtual_refresh_enabled() -> bool {
std::env::var("PUNKTFUNK_MUTTER_VIRTUAL_REFRESH")
.map(|v| {
matches!(
v.trim().to_ascii_lowercase().as_str(),
"1" | "true" | "yes" | "on"
)
})
.unwrap_or(false)
}
/// A DisplayConfig proxy on its own session-bus connection (owned, so it stays alive for the
/// session — independent of the RemoteDesktop/ScreenCast connection).
async fn display_config() -> Result<zbus::Proxy<'static>> {