valentine

presetcheck.rs (2244B)

---

 //! Preset round-trip diagnostic (READ-ONLY apart from re-applying identical
 //! values). Answers: "does save→load change anything?" by capturing the full
 //! device state, then comparing it field-by-field to a preset built from it —
 //! and reporting any mixer crosspoints that differ from unity expectations.
 //!
 //! It does NOT change routing or toggles; it only reads. Run with Focusrite
 //! Control quit:  cargo run -p spike --bin presetcheck
 
 use scarlett_core::matrix::mixer_value_to_db;
 use scarlett_core::model::S18I20_GEN3;
 use scarlett_core::{Scarlett, UsbTransport};
 
 fn main() {
     if let Err(e) = run() {
         eprintln!("\x1b[31mPRESETCHECK FAILED:\x1b[0m {e}");
         std::process::exit(1);
     }
 }
 
 fn run() -> Result<(), Box<dyn std::error::Error>> {
     let mut dev = Scarlett::new(UsbTransport::open_default()?);
     dev.init()?;
     println!("connected: {}\n", S18I20_GEN3.name);
 
     // Read the mixer matrix and report any non-(-inf / 0dB) crosspoints, plus the
     // peak gain — a mix summing many sources at 0 dB is how things get loud.
     let inputs = S18I20_GEN3.mixer_inputs() as usize;
     let buses = S18I20_GEN3.mix_buses();
     println!("=== MIXER (non-silent crosspoints) ===");
     let mut hot = 0;
     let mut active_per_bus = vec![0u32; buses as usize];
     for bus in 0..buses {
         let raw = dev.get_mix(bus, inputs)?;
         for (i, &v) in raw.iter().enumerate() {
             let db = mixer_value_to_db(v);
             if db > -79.0 {
                 active_per_bus[bus as usize] += 1;
                 if db >= -0.1 {
                     hot += 1;
                 }
                 if active_per_bus[bus as usize] <= 6 {
                     println!("  bus {bus:>2} ← in {:>2}: {db:>6.1} dB", i + 1);
                 }
             }
         }
     }
     println!("\nper-bus active crosspoint counts: {active_per_bus:?}");
     println!("crosspoints at ~0 dB (unity): {hot}");
     println!(
         "\nNote: if a mix bus sums many sources at 0 dB, that bus is HOT by design\n\
          (summing 4 unity signals ≈ +12 dB). Lowering those crosspoints is the\n\
          only device-side level control on this model."
     );
 
     println!("\nPRESETCHECK DONE (read-only).");
     Ok(())
 }