feature: add on-demand vrr (#586)

* feature: add on-demand vrr

* Don't require connector::Info in try_to_set_vrr

* Improve VRR help message

* Rename connector_handle => connector

* Fix tracy span name

* Move on demand vrr flag set higher

* wiki: Mention on-demand VRR

---------

Co-authored-by: Ivan Molodetskikh <yalterz@gmail.com>

1 files changed, 50 insertions, 38 deletions

diff --git a/src/backend/tty.rs b/src/backend/tty.rs
index 10becafe..1d891d91 100644
--- a/src/backend/tty.rs
+++ b/src/backend/tty.rs
@@ -180,6 +180,7 @@ struct TtyOutputState {
 struct Surface {
     name: String,
     compositor: GbmDrmCompositor,
+    connector: connector::Handle,
     dmabuf_feedback: Option<SurfaceDmabufFeedback>,
     gamma_props: Option<GammaProps>,
     /// Gamma change to apply upon session resume.
@@ -426,18 +427,6 @@ impl Tty {
                         }
 
                         // Restore VRR.
-                        let Some(connector) =
-                            surface.compositor.pending_connectors().into_iter().next()
-                        else {
-                            error!("surface pending connectors is empty");
-                            continue;
-                        };
-                        let Some(connector) = device.drm_scanner.connectors().get(&connector)
-                        else {
-                            error!("missing enabled connector in drm_scanner");
-                            continue;
-                        };
-
                         let output = niri
                             .global_space
                             .outputs()
@@ -457,7 +446,7 @@ impl Tty {
 
                         try_to_change_vrr(
                             &device.drm,
-                            connector,
+                            surface.connector,
                             *crtc,
                             surface,
                             output_state,
@@ -832,15 +821,13 @@ impl Tty {
         let mut vrr_enabled = false;
         if let Some(capable) = is_vrr_capable(&device.drm, connector.handle()) {
             if capable {
-                let word = if config.variable_refresh_rate {
-                    "enabling"
-                } else {
-                    "disabling"
-                };
+                // Even if on-demand, we still disable it until later checks.
+                let vrr = config.is_vrr_always_on();
+                let word = if vrr { "enabling" } else { "disabling" };
 
-                match set_vrr_enabled(&device.drm, crtc, config.variable_refresh_rate) {
+                match set_vrr_enabled(&device.drm, crtc, vrr) {
                     Ok(enabled) => {
-                        if enabled != config.variable_refresh_rate {
+                        if enabled != vrr {
                             warn!("failed {} VRR", word);
                         }
 
@@ -851,13 +838,13 @@ impl Tty {
                     }
                 }
             } else {
-                if config.variable_refresh_rate {
+                if !config.is_vrr_always_off() {
                     warn!("cannot enable VRR because connector is not vrr_capable");
                 }
 
                 // Try to disable it anyway to work around a bug where resetting DRM state causes
                 // vrr_capable to be reset to 0, potentially leaving VRR_ENABLED at 1.
-                let res = set_vrr_enabled(&device.drm, crtc, config.variable_refresh_rate);
+                let res = set_vrr_enabled(&device.drm, crtc, false);
                 if matches!(res, Ok(true)) {
                     warn!("error disabling VRR");
 
@@ -865,7 +852,7 @@ impl Tty {
                     vrr_enabled = true;
                 }
             }
-        } else if config.variable_refresh_rate {
+        } else if !config.is_vrr_always_off() {
             warn!("cannot enable VRR because connector is not vrr_capable");
         }
 
@@ -1017,6 +1004,7 @@ impl Tty {
 
         let surface = Surface {
             name: output_name.clone(),
+            connector: connector.handle(),
             compositor,
             dmabuf_feedback,
             gamma_props,
@@ -1661,6 +1649,33 @@ impl Tty {
         }
     }
 
+    pub fn set_output_on_demand_vrr(&mut self, niri: &mut Niri, output: &Output, enable_vrr: bool) {
+        let _span = tracy_client::span!("Tty::set_output_on_demand_vrr");
+
+        let output_state = niri.output_state.get_mut(output).unwrap();
+        output_state.on_demand_vrr_enabled = enable_vrr;
+        if output_state.frame_clock.vrr() == enable_vrr {
+            return;
+        }
+        for (&node, device) in self.devices.iter_mut() {
+            for (&crtc, surface) in device.surfaces.iter_mut() {
+                let tty_state: &TtyOutputState = output.user_data().get().unwrap();
+                if tty_state.node == node && tty_state.crtc == crtc {
+                    try_to_change_vrr(
+                        &device.drm,
+                        surface.connector,
+                        crtc,
+                        surface,
+                        output_state,
+                        enable_vrr,
+                    );
+                    self.refresh_ipc_outputs(niri);
+                    return;
+                }
+            }
+        }
+    }
+
     pub fn on_output_config_changed(&mut self, niri: &mut Niri) {
         let _span = tracy_client::span!("Tty::on_output_config_changed");
 
@@ -1675,9 +1690,7 @@ impl Tty {
         let mut to_connect = vec![];
 
         for (&node, device) in &mut self.devices {
-            for surface in device.surfaces.values_mut() {
-                let crtc = surface.compositor.crtc();
-
+            for (&crtc, surface) in device.surfaces.iter_mut() {
                 let config = self
                     .config
                     .borrow()
@@ -1691,12 +1704,8 @@ impl Tty {
                 }
 
                 // Check if we need to change the mode.
-                let Some(connector) = surface.compositor.pending_connectors().into_iter().next()
+                let Some(connector) = device.drm_scanner.connectors().get(&surface.connector)
                 else {
-                    error!("surface pending connectors is empty");
-                    continue;
-                };
-                let Some(connector) = device.drm_scanner.connectors().get(&connector) else {
                     error!("missing enabled connector in drm_scanner");
                     continue;
                 };
@@ -1707,8 +1716,9 @@ impl Tty {
                 };
 
                 let change_mode = surface.compositor.pending_mode() != mode;
-                let change_vrr = surface.vrr_enabled != config.variable_refresh_rate;
-                if !change_mode && !change_vrr {
+                let change_always_vrr = surface.vrr_enabled != config.is_vrr_always_on();
+                let is_on_demand_vrr = config.is_vrr_on_demand();
+                if !change_mode && !change_always_vrr && !is_on_demand_vrr {
                     continue;
                 }
 
@@ -1729,14 +1739,16 @@ impl Tty {
                     continue;
                 };
 
-                if change_vrr {
+                if (is_on_demand_vrr && surface.vrr_enabled != output_state.on_demand_vrr_enabled)
+                    || (!is_on_demand_vrr && change_always_vrr)
+                {
                     try_to_change_vrr(
                         &device.drm,
-                        connector,
+                        connector.handle(),
                         crtc,
                         surface,
                         output_state,
-                        config.variable_refresh_rate,
+                        !surface.vrr_enabled,
                     );
                 }
 
@@ -2388,7 +2400,7 @@ pub fn set_gamma_for_crtc(
 
 fn try_to_change_vrr(
     device: &DrmDevice,
-    connector: &connector::Info,
+    connector: connector::Handle,
     crtc: crtc::Handle,
     surface: &mut Surface,
     output_state: &mut crate::niri::OutputState,
@@ -2396,7 +2408,7 @@ fn try_to_change_vrr(
 ) {
     let _span = tracy_client::span!("try_to_change_vrr");
 
-    if is_vrr_capable(device, connector.handle()) == Some(true) {
+    if is_vrr_capable(device, connector) == Some(true) {
         let word = if enable_vrr { "enabling" } else { "disabling" };
 
         match set_vrr_enabled(device, crtc, enable_vrr) {