diff -Nru alsa-lib-1.2.2/debian/changelog alsa-lib-1.2.2/debian/changelog
--- alsa-lib-1.2.2/debian/changelog	2020-06-16 17:52:07.000000000 +0800
+++ alsa-lib-1.2.2/debian/changelog	2020-08-13 23:02:37.000000000 +0800
@@ -1,3 +1,10 @@
+alsa-lib (1.2.2-2.1ubuntu1.1) focal; urgency=medium
+
+  * d/p/0001-conf-USB-Audio-Disable-IEC958-on-Lenovo-ThinkStation.patch
+    - Disable IEC958 on Lenovo ThinkStation P620 (LP: #1891461)
+
+ -- Kai-Heng Feng <kai.heng.feng@canonical.com>  Thu, 13 Aug 2020 23:02:37 +0800
+
 alsa-lib (1.2.2-2.1ubuntu1) focal; urgency=medium
 
   * debian/patches/0001-conf-USB-Audio-Add-HP-Thunderbolt-Dock-in-the-IEC958.patch:
diff -Nru alsa-lib-1.2.2/debian/patches/0001-conf-USB-Audio-Disable-IEC958-on-Lenovo-ThinkStation.patch alsa-lib-1.2.2/debian/patches/0001-conf-USB-Audio-Disable-IEC958-on-Lenovo-ThinkStation.patch
--- alsa-lib-1.2.2/debian/patches/0001-conf-USB-Audio-Disable-IEC958-on-Lenovo-ThinkStation.patch	1970-01-01 08:00:00.000000000 +0800
+++ alsa-lib-1.2.2/debian/patches/0001-conf-USB-Audio-Disable-IEC958-on-Lenovo-ThinkStation.patch	2020-08-13 23:02:06.000000000 +0800
@@ -0,0 +1,30 @@
+From 464c2f8b61855cb22d61c4b232f74d6767fac5fb Mon Sep 17 00:00:00 2001
+From: Kai-Heng Feng <kai.heng.feng@canonical.com>
+Date: Mon, 3 Aug 2020 23:57:45 +0800
+Subject: [PATCH] conf: USB-Audio: Disable IEC958 on Lenovo ThinkStation P620
+
+Both USB audio cards on Lenovo ThinkStation P620 don't support IEC958,
+so disable IEC958 accordingly.
+
+Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
+Signed-off-by: Takashi Iwai <tiwai@suse.de>
+---
+ src/conf/cards/USB-Audio.conf | 2 ++
+ 1 file changed, 2 insertions(+)
+
+diff --git a/src/conf/cards/USB-Audio.conf b/src/conf/cards/USB-Audio.conf
+index 297629f3..9b64af3c 100644
+--- a/src/conf/cards/USB-Audio.conf
++++ b/src/conf/cards/USB-Audio.conf
+@@ -63,6 +63,8 @@ USB-Audio.pcm.iec958_device {
+ 	"Scarlett 2i4 USB" 999
+ 	"Sennheiser USB headset" 999
+ 	"SWTOR Gaming Headset by Razer" 999
++	"ThinkStation P620 Main" 999
++	"ThinkStation P620 Rear" 999
+ 	"Thunderbolt Dock Audio Headset" 999
+ 	"Thunderbolt Dock Audio Module" 999
+ 	"USB Device 0x46d_0x821" 999
+-- 
+2.17.1
+
diff -Nru alsa-lib-1.2.2/debian/patches/series alsa-lib-1.2.2/debian/patches/series
--- alsa-lib-1.2.2/debian/patches/series	2020-06-16 17:52:07.000000000 +0800
+++ alsa-lib-1.2.2/debian/patches/series	2020-08-13 23:02:19.000000000 +0800
@@ -1,3 +1,4 @@
 0001-Enabled-extended-namehints-in-alsa.conf.patch
 python3.8.diff
 0001-conf-USB-Audio-Add-HP-Thunderbolt-Dock-in-the-IEC958.patch
+0001-conf-USB-Audio-Disable-IEC958-on-Lenovo-ThinkStation.patch