fix(audio): add uac clock alignment override

Cargo.lock

@@ -1642,7 +1642,7 @@ checksum = "09edd9e8b54e49e587e4f6295a7d29c3ea94d469cb40ab8ca70b288248a81db2"
 
 [[package]]
 name = "lesavka_client"
-version = "0.13.5"
+version = "0.13.6"
 dependencies = [
  "anyhow",
  "async-stream",
@@ -1676,7 +1676,7 @@ dependencies = [
 
 [[package]]
 name = "lesavka_common"
-version = "0.13.5"
+version = "0.13.6"
 dependencies = [
  "anyhow",
  "base64",
@@ -1688,7 +1688,7 @@ dependencies = [
 
 [[package]]
 name = "lesavka_server"
-version = "0.13.5"
+version = "0.13.6"
 dependencies = [
  "anyhow",
  "base64",

client/Cargo.toml

@@ -4,7 +4,7 @@ path                    = "src/main.rs"
 
 [package]
 name                    = "lesavka_client"
-version                 = "0.13.5"
+version                 = "0.13.6"
 edition                 = "2024"
 
 [dependencies]

common/Cargo.toml

@@ -1,6 +1,6 @@
 [package]
 name                    = "lesavka_common"
-version                 = "0.13.5"
+version                 = "0.13.6"
 edition                 = "2024"
 build                   = "build.rs"
 

docs/operational-env.md

@@ -187,6 +187,7 @@ Hardware-facing assumptions belong near the code that uses them; this file is th
 | `LESAVKA_UAC_DEV` | server hardware/device override |
 | `LESAVKA_UAC_HDMI_COMPENSATION_US` | server HDMI audio sink latency override |
 | `LESAVKA_UAC_LATENCY_TIME_US` | server audio sink latency override |
+| `LESAVKA_UAC_SESSION_CLOCK_ALIGN` | server audio sink clock-alignment override |
 | `LESAVKA_TEST_CAM_U32` | test/build contract variable; not runtime operator config |
 | `LESAVKA_TEST_CAP_CAMERA` | test/build contract variable; not runtime operator config |
 | `LESAVKA_TEST_CAP_MIC` | test/build contract variable; not runtime operator config |
@@ -211,6 +212,7 @@ Hardware-facing assumptions belong near the code that uses them; this file is th
 | `LESAVKA_TEST_VIDEO_SOURCE` | test/build contract variable; not runtime operator config |
 | `LESAVKA_TOUCHPAD_SCALE` | input routing/clipboard override |
 | `LESAVKA_UAC_DEV` | server hardware/device override |
+| `LESAVKA_UAC_SESSION_CLOCK_ALIGN` | disable only for A/B diagnosing UAC sink timing vs silence |
 | `LESAVKA_UPLINK_CAMERA_PREVIEW` | client media capture/playback override |
 | `LESAVKA_UPLINK_MIC_LEVEL` | client media capture/playback override |
 | `LESAVKA_USB_RECOVERY_` | USB recovery timing override |

scripts/install/server.sh

@@ -437,6 +437,7 @@ fi
   printf 'LESAVKA_UAC_DEV=%s\n' "${LESAVKA_UAC_DEV:-hw:UAC2Gadget,0}"
   printf 'LESAVKA_ALSA_DEV=%s\n' "${LESAVKA_ALSA_DEV:-hw:UAC2Gadget,0}"
   printf 'LESAVKA_UAC_HDMI_COMPENSATION_US=%s\n' "${LESAVKA_UAC_HDMI_COMPENSATION_US:-0}"
+  printf 'LESAVKA_UAC_SESSION_CLOCK_ALIGN=%s\n' "${LESAVKA_UAC_SESSION_CLOCK_ALIGN:-1}"
 } | sudo tee /etc/lesavka/server.env >/dev/null
 
 echo "==> 6a. Systemd units - lesavka-core"

server/Cargo.toml

@@ -10,7 +10,7 @@ bench                   = false
 
 [package]
 name                    = "lesavka_server"
-version                 = "0.13.5"
+version                 = "0.13.6"
 edition                 = "2024"
 autobins                = false
 

server/src/audio/voice_input.rs

@@ -106,6 +106,19 @@ fn non_negative_voice_sink_timing_env(name: &str, default: i64) -> i64 {
         .unwrap_or(default)
 }
 
+fn voice_sink_session_clock_align_enabled() -> bool {
+    std::env::var("LESAVKA_UAC_SESSION_CLOCK_ALIGN")
+        .ok()
+        .map(|value| {
+            let trimmed = value.trim();
+            !(trimmed.eq_ignore_ascii_case("0")
+                || trimmed.eq_ignore_ascii_case("false")
+                || trimmed.eq_ignore_ascii_case("no")
+                || trimmed.eq_ignore_ascii_case("off"))
+        })
+        .unwrap_or(true)
+}
+
 impl Voice {
     #[cfg(coverage)]
     pub async fn new(_alsa_dev: &str) -> anyhow::Result<Self> {
@@ -196,10 +209,11 @@ impl Voice {
         let buffer_time_us = voice_sink_buffer_time_us();
         let latency_time_us = voice_sink_latency_time_us();
         let compensation_us = voice_sink_compensation_us();
+        let clock_align_enabled = voice_sink_session_clock_align_enabled();
 
         alsa_sink.set_property("device", alsa_dev);
-        alsa_sink.set_property("sync", true);
+        alsa_sink.set_property("sync", clock_align_enabled);
-        alsa_sink.set_property("async", true);
+        alsa_sink.set_property("async", clock_align_enabled);
         alsa_sink.set_property("enable-last-sample", false);
         alsa_sink.set_property("provide-clock", false);
         alsa_sink.set_property("buffer-time", buffer_time_us);
@@ -214,9 +228,12 @@ impl Voice {
             buffer_time_us,
             latency_time_us,
             compensation_us,
+            clock_align_enabled,
             "🎤 UAC sink low-latency timing armed"
         );
-        crate::media_timing::prepare_pipeline_clock_sync(&pipeline);
+        if clock_align_enabled {
+            crate::media_timing::prepare_pipeline_clock_sync(&pipeline);
+        }
 
         pipeline.add_many([
             appsrc.upcast_ref(),
@@ -273,7 +290,7 @@ impl Voice {
         Ok(Self {
             appsrc,
             _pipe: pipeline,
-            clock_aligned: false,
+            clock_aligned: !clock_align_enabled,
             tap: ClipTap::new("voice", Duration::from_secs(60)),
         })
     }
@@ -389,4 +406,21 @@ mod voice_sink_timing_tests {
             });
         });
     }
+
+    #[test]
+    fn session_clock_alignment_defaults_on_and_accepts_disable_overrides() {
+        temp_env::with_var_unset("LESAVKA_UAC_SESSION_CLOCK_ALIGN", || {
+            assert!(super::voice_sink_session_clock_align_enabled());
+        });
+
+        for disabled in ["0", "false", "no", "off"] {
+            temp_env::with_var("LESAVKA_UAC_SESSION_CLOCK_ALIGN", Some(disabled), || {
+                assert!(!super::voice_sink_session_clock_align_enabled());
+            });
+        }
+
+        temp_env::with_var("LESAVKA_UAC_SESSION_CLOCK_ALIGN", Some("1"), || {
+            assert!(super::voice_sink_session_clock_align_enabled());
+        });
+    }
 }