chore: Don't query audio devices on linux (#2303)

alvr/server_io/Cargo.toml

@@ -13,8 +13,10 @@ alvr_filesystem.workspace = true
 alvr_packets.workspace = true
 alvr_session.workspace = true
 
-cpal = { version = "0.15", features = ["jack"] }
 encoding_rs_io = "0.1"
 dirs = "5"
 runas = "^1.2" # version 1.1 is broken
 serde_json = "1"
+
+[target.'cfg(not(target_os = "linux"))'.dependencies]
+cpal = "0.15"

alvr/server_io/src/lib.rs

@@ -13,7 +13,6 @@ use alvr_common::{
 use alvr_events::EventType;
 use alvr_packets::{AudioDevicesList, ClientListAction, PathSegment, PathValuePair};
 use alvr_session::{ClientConnectionConfig, SessionConfig, Settings};
-use cpal::traits::{DeviceTrait, HostTrait};
 use serde_json as json;
 use std::{
     collections::{hash_map::Entry, HashMap},
@@ -290,18 +289,30 @@ impl ServerDataManager {
     }
 
     pub fn get_audio_devices_list(&self) -> Result<AudioDevicesList> {
-        let host = cpal::default_host();
-
-        let output = host
-            .output_devices()?
-            .filter_map(|d| d.name().ok())
-            .collect::<Vec<_>>();
-        let input = host
-            .input_devices()?
-            .filter_map(|d| d.name().ok())
-            .collect::<Vec<_>>();
-
-        Ok(AudioDevicesList { output, input })
+        #[cfg(not(target_os = "linux"))]
+        {
+            use cpal::traits::{DeviceTrait, HostTrait};
+
+            let host = cpal::default_host();
+
+            let output = host
+                .output_devices()?
+                .filter_map(|d| d.name().ok())
+                .collect::<Vec<_>>();
+            let input = host
+                .input_devices()?
+                .filter_map(|d| d.name().ok())
+                .collect::<Vec<_>>();
+
+            Ok(AudioDevicesList { output, input })
+        }
+        #[cfg(target_os = "linux")]
+        {
+            Ok(AudioDevicesList {
+                input: vec![],
+                output: vec![],
+            })
+        }
     }
 }