1 files changed, 6 insertions, 1 deletions

diff --git a/rsnix/src/ehci.rs b/rsnix/src/ehci.rs
index 6209155..8baa0ad 100644
--- a/rsnix/src/ehci.rs
+++ b/rsnix/src/ehci.rs
@@ -89,7 +89,12 @@ static QR_SHOWN: AtomicBool = AtomicBool::new(false);
 // DEBUG: run the one-boot transfer variant matrix (real-hardware bisection
 // of the EHCI System Error trigger).  MATRIX_DONE gates it to one pass;
 // XFER_TWEAK flips construction variables inside ctl_xfer.
-static DEBUG_MATRIX: bool = true;
+//
+// OFF in normal builds: with it on, `enumerate()` is replaced by the
+// diagnostic matrix and returns false, i.e. the EHCI driver never brings a
+// device up.  Flip to true only when bisecting a hardware fault, and expect
+// no USB input in that build.
+static DEBUG_MATRIX: bool = false;
 static MATRIX_DONE: AtomicBool = AtomicBool::new(false);
 static XFER_TWEAK: AtomicU32 = AtomicU32::new(0);
 // Low-region (<1 MB) control QH for the matrix's low-region variant.