Fix NuForce uDAC USB disconnects

Cheap Savitech chip firmware stalls on rapid SET_INTERFACE / sample-rate
renegotiation, eventually dropping off the USB bus and requiring a
physical replug. Two fixes, both scoped to this exact device only:

- snd_usb_audio quirk_flags (262a:10aa): fixed_rate + ctl_msg_delay +
  iface_delay, applied via /etc/modprobe.d during bootstrap.
- WirePlumber: disable idle-suspend for the device's ALSA node so
  PipeWire doesn't repeatedly reopen the stream during normal use.

.config/wireplumber/wireplumber.conf.d/51-nuforce-no-suspend.conf

@@ -0,0 +1,23 @@
+# The NuForce uDAC (Savitech chip) has flaky firmware: when PipeWire
+# idles and then resumes its ALSA node, the device often fails the
+# resulting SET_INTERFACE / sample-rate renegotiation with a USB stall
+# (spa.alsa: set_hw_params: Broken pipe). Enough of these in a row make
+# the device drop off the USB bus and require a physical replug.
+#
+# Keeping the node's hardware stream open (no idle-suspend) avoids the
+# repeated renegotiation and stops the crashes.
+
+monitor.alsa.rules = [
+  {
+    matches = [
+      {
+        node.name = "~alsa_output.usb-Nuforce_Inc\\._NuForce_USB_Audio-.*"
+      }
+    ]
+    actions = {
+      update-props = {
+        session.suspend-timeout-seconds = 0
+      }
+    }
+  }
+]

.config/yadm/bootstrap##distro.arch

@@ -68,6 +68,22 @@ EOF
 
 sudo systemctl reload sshd
 
+# --- NuForce uDAC USB audio quirks --------------------------------------
+# This DAC's firmware (262a:10aa) stalls on rapid SET_INTERFACE / sample
+# rate renegotiation, which without these quirks eventually drops the
+# device off the USB bus and requires a physical replug. Scoped to this
+# exact VID:PID so it's a no-op on any machine without the device
+# attached. Takes effect next time snd_usb_audio (re)probes the device
+# (reboot, module reload, or replug) -- not applied retroactively here.
+sudo install -d -m 755 /etc/modprobe.d
+sudo tee /etc/modprobe.d/nuforce-udac-quirks.conf > /dev/null <<'EOF'
+# fixed_rate (bit 21): device only offers one sample rate; stop the
+#   driver re-sending SET_CUR for it ("cannot set freq 48000 to ep 0x3").
+# ctl_msg_delay (bit 8): 20ms pause around each USB control message.
+# iface_delay (bit 11): 50ms pause around each SET_INTERFACE call.
+options snd_usb_audio quirk_flags=262a:10aa:0x200900
+EOF
+
 if [ ! -d "$HOME/repos/yay" ]; then
 	mkdir -p "$HOME/repos"
 	cd "$HOME/repos"