From a1837d2d8088ec8b7334106ec3c1929a1c1b08fd Mon Sep 17 00:00:00 2001
From: Dana Conrad <dconrad@fastmail.com>
Date: Sat, 8 Nov 2025 15:12:58 +0000
Subject: [PATCH] usbaudio: block playback while usbaudio is active

Needed due to us commandeering the AUDIO DSP "channel" for USBAudio.
If/When we add another DSP channel, this can be reverted.

Works, but still goes to a "blank" WPS screen for a split second before
cancelling out.

Change-Id: I5fb8a1e226b4d3e46c86c59d593d807f49d7a35f
---
 apps/playback.c               | 15 +++++++++++++++
 firmware/usbstack/usb_audio.c | 10 ++++++++++
 firmware/usbstack/usb_audio.h |  3 +++
 3 files changed, 28 insertions(+)

diff --git a/apps/playback.c b/apps/playback.c
index 381c474415..8a32772865 100644
--- a/apps/playback.c
+++ b/apps/playback.c
@@ -65,6 +65,12 @@
 #include <strings.h>  /* For strncasecmp() */
 #endif
 
+#ifdef USB_ENABLE_AUDIO
+#include "usbstack/usb_audio.h"
+#include "splash.h"
+#include "lang.h"
+#endif
+
 /* TODO: The audio thread really is doing multitasking of acting like a
          consumer and producer of tracks. It may be advantageous to better
          logically separate the two functions. I won't go that far just yet. */
@@ -2978,6 +2984,15 @@ static void audio_on_track_changed(void)
 static void audio_start_playback(const struct audio_resume_info *resume_info,
                                  unsigned int flags)
 {
+/* NOTE: if USBAudio ever gets its own DSP channel, this block can go away! */
+#ifdef USB_ENABLE_AUDIO
+    if (usb_audio_get_active())
+    {
+        splash(HZ*2, str(LANG_USB_DAC_ACTIVE));
+        queue_reply(&audio_queue, 0);
+        return;
+    }
+#endif
     static struct audio_resume_info resume = { 0, 0 };
     enum play_status old_status = play_status;
 
diff --git a/firmware/usbstack/usb_audio.c b/firmware/usbstack/usb_audio.c
index 321f4405c1..de67cdf366 100644
--- a/firmware/usbstack/usb_audio.c
+++ b/firmware/usbstack/usb_audio.c
@@ -398,6 +398,9 @@ int buffers_filled_max_last;
 static int last_frame = 0;
 static int frames_dropped = 0;
 
+/* for blocking normal playback */
+static bool usbaudio_active = false;
+
 /* Schematic view of the RX situation:
  * (in case NR_BUFFERS = 4)
  *
@@ -1181,6 +1184,7 @@ void usb_audio_init_connection(void)
 {
     logf("usbaudio: init connection");
 
+    usbaudio_active = true;
     dsp = dsp_get_config(CODEC_IDX_AUDIO);
     dsp_configure(dsp, DSP_RESET, 0);
     dsp_configure(dsp, DSP_SET_STEREO_MODE, STEREO_INTERLEAVED);
@@ -1202,6 +1206,12 @@ void usb_audio_disconnect(void)
 
     usb_audio_stop_playback();
     usb_audio_free_buf();
+    usbaudio_active = false;
+}
+
+bool usb_audio_get_active(void)
+{
+    return usbaudio_active;
 }
 
 bool usb_audio_get_alloc_failed(void)
diff --git a/firmware/usbstack/usb_audio.h b/firmware/usbstack/usb_audio.h
index 209efccaa6..ebe5542da0 100644
--- a/firmware/usbstack/usb_audio.h
+++ b/firmware/usbstack/usb_audio.h
@@ -20,6 +20,7 @@
 #define USB_AUDIO_H
 
 #include "usb_ch9.h"
+#include "usb_class_driver.h"
 
 /* NOTE
  *
@@ -276,4 +277,6 @@ int usb_audio_get_frames_dropped(void);
  */
 int usb_audio_get_cur_volume(void);
 
+bool usb_audio_get_active(void);
+
 #endif