kms: Drop early_import as it seems to hurt performance

src/backend/kms/mod.rs

@@ -1229,7 +1229,9 @@ impl Surface {
                     Ok(()) => {
                         self.pending = true;
                     }
-                    Err(FrameError::EmptyFrame) => {}
+                    Err(FrameError::EmptyFrame) => {
+                        tracing::debug!("Stopped rendering");
+                    }
                     Err(err) => {
                         return Err(err).with_context(|| "Failed to submit result for display")
                     }
@@ -1517,19 +1519,6 @@ impl KmsState {
             .copied()
     }
 
-    pub fn try_early_import(
-        &mut self,
-        surface: &WlSurface,
-        output: &Output,
-        target: DrmNode,
-        shell: &Shell,
-    ) {
-        let render = render_node_for_output(&output, self.primary_node, target, &shell);
-        if let Err(err) = self.api.early_import(render, surface) {
-            trace!(?err, "Early import failed.");
-        }
-    }
-
     pub fn dmabuf_imported(
         &mut self,
         _client: Option<Client>,

src/wayland/handlers/compositor.rs

@@ -1,9 +1,7 @@
 // SPDX-License-Identifier: GPL-3.0-only
 
 use crate::{
-    shell::CosmicSurface,
+    shell::CosmicSurface, state::ClientState, utils::prelude::*,
-    state::{BackendData, ClientState},
-    utils::prelude::*,
     wayland::protocols::screencopy::SessionType,
 };
 use calloop::Interest;
@@ -33,19 +31,6 @@ use std::sync::Mutex;
 use super::screencopy::PendingScreencopyBuffers;
 
 impl State {
-    fn early_import_surface(&mut self, surface: &WlSurface) {
-        let mut import_nodes = std::collections::HashSet::new();
-        if let Some(output) = self.common.shell.visible_output_for_surface(&surface) {
-            if let BackendData::Kms(ref mut kms_state) = &mut self.backend {
-                if let Some(target) = kms_state.target_node_for_output(&output) {
-                    if import_nodes.insert(target) {
-                        kms_state.try_early_import(surface, &output, target, &self.common.shell);
-                    }
-                }
-            }
-        }
-    }
-
     fn toplevel_ensure_initial_configure(&mut self, toplevel: &ToplevelSurface) -> bool {
         // send the initial configure if relevant
         let initial_configure_sent = with_states(toplevel.wl_surface(), |states| {
@@ -225,10 +210,6 @@ impl CompositorHandler for State {
         //handle window screencopy sessions
         self.schedule_window_session(surface);
 
-        // We need to know every potential output for importing to the right gpu and scheduling a render,
-        // so call this only after every potential surface map operation has been done.
-        self.early_import_surface(surface);
-
         // and refresh smithays internal state
         self.common.shell.popups.commit(surface);