From 131a41d53053c2f561395801556cdb45417a383a Mon Sep 17 00:00:00 2001
From: Steven Dan <guang1025@163.com>
Date: Tue, 26 May 2026 09:47:47 +0800
Subject: [PATCH] fix v71 boot noise

---
 .../app_usb_aud_fosi_c1_v71/src/extensions/dsp.c       | 10 ++++++++--
 1 file changed, 8 insertions(+), 2 deletions(-)

diff --git a/sw_usb_audio/app_usb_aud_fosi_c1_v71/src/extensions/dsp.c b/sw_usb_audio/app_usb_aud_fosi_c1_v71/src/extensions/dsp.c
index 347048f..2bb1373 100644
--- a/sw_usb_audio/app_usb_aud_fosi_c1_v71/src/extensions/dsp.c
+++ b/sw_usb_audio/app_usb_aud_fosi_c1_v71/src/extensions/dsp.c
@@ -274,6 +274,8 @@ void UserBufferManagementInit(unsigned sampFreq)
         clear_ring_buffer(3);
     }
 #endif
+    memset(ubm_ingress, 0, sizeof(ubm_ingress));
+    memset(ubm_egress,  0, sizeof(ubm_egress));
 #if 0// USE_EX3D == 1
     memset(ubm_ingress, 0, sizeof(ubm_ingress));
     memset(ubm_egress,  0, sizeof(ubm_egress));
@@ -303,6 +305,12 @@ void UserBufferManagementInit(unsigned sampFreq)
                         EX3D_TO_UBM_CHANS * DSP_BLOCK_LENGTH);
       memset(ubm_ingress, 0, sizeof(ubm_ingress));  // 清掉哑帧输出
 #endif
+          // ② 预热：推一个零帧穿过 ex3d，触发所有 worker 加载 + 首次同步
+      chan_out_buf_word(uc_ex3d_to_ubm, (const uint32_t *)ubm_egress,
+                        UBM_TO_EX3D_CHANS * DSP_BLOCK_LENGTH);
+      chan_in_buf_word (uc_ex3d_to_ubm, (uint32_t *)ubm_ingress,
+                        EX3D_TO_UBM_CHANS * DSP_BLOCK_LENGTH);
+      memset(ubm_ingress, 0, sizeof(ubm_ingress));  // 清掉哑帧输出
 }
 float fLevel[NUM_USB_CHAN_OUT] = {0,};
 enum {UBM_A3D_OFF=0, UBM_A3D_VON=1, UBM_A3D_ON=2};
@@ -1298,7 +1306,6 @@ void ex3d_task(chanend_t c_ex3d_to_ubm){
     memset(ubm_egress,  0, sizeof(ubm_egress));
     audio_ex3d_onoff(1);
 	
-#if !UAC1_MODE
     Ex3dOffGain = -5;
     Ex3dOnGain = -5;
     Ex3dLfeGain = -5;
@@ -1339,7 +1346,6 @@ void ex3d_task(chanend_t c_ex3d_to_ubm){
         tx1_apply_ex3d_for_game_mode(init_gm);
         g_tx1_last_ex3d_game_applied = init_gm;
     }
-#endif
 #endif
 
     while (1) {