alsa-mixer: add mono input support for Behringer UMC22

src/modules/alsa/90-pulseaudio.rules

@@ -110,6 +110,7 @@ ATTRS{idVendor}=="0763", ATTRS{idProduct}=="2012", ENV{PULSE_PROFILE_SET}="maudi
 ATTRS{idVendor}=="045e", ATTRS{idProduct}=="02bb", ENV{PULSE_PROFILE_SET}="kinect-audio.conf"
 ATTRS{idVendor}=="041e", ATTRS{idProduct}=="322c", ENV{PULSE_PROFILE_SET}="sb-omni-surround-5.1.conf"
 ATTRS{idVendor}=="0bda", ATTRS{idProduct}=="4014", ENV{PULSE_PROFILE_SET}="dell-dock-tb16-usb-audio.conf"
+ATTRS{idVendor}=="08bb", ATTRS{idProduct}=="2902", ENV{PULSE_PROFILE_SET}="behringer-umc22.conf"
 
 # ID 1038:12ad is for the 2018 refresh of the Arctis 7.
 # ID 1038:1294 is for Arctis Pro Wireless (which works with the Arctis 7 configuration).

src/modules/alsa/alsa-mixer.c

@@ -4392,6 +4392,8 @@ static int mapping_verify(pa_alsa_mapping *m, const pa_channel_map *bonus) {
 
     static const struct description_map well_known_descriptions[] = {
         { "analog-mono",            N_("Analog Mono") },
+        { "analog-mono-left",       N_("Analog Mono (Left)") },
+        { "analog-mono-right",      N_("Analog Mono (Right)") },
         { "analog-stereo",          N_("Analog Stereo") },
         { "mono-fallback",          N_("Mono") },
         { "stereo-fallback",        N_("Stereo") },

src/modules/alsa/mixer/profile-sets/behringer-umc22.conf

@@ -0,0 +1,68 @@
+# This file is part of PulseAudio.
+#
+# PulseAudio is free software; you can redistribute it and/or modify
+# it under the terms of the GNU Lesser General Public License as
+# published by the Free Software Foundation; either version 2.1 of the
+# License, or (at your option) any later version.
+#
+# PulseAudio is distributed in the hope that it will be useful, but
+# WITHOUT ANY WARRANTY; without even the implied warranty of
+# MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+# General Public License for more details.
+#
+# You should have received a copy of the GNU Lesser General Public License
+# along with PulseAudio; if not, see <http://www.gnu.org/licenses/>.
+
+; Behringer U-Phoria UMC22
+;
+; Default mapping only allows to use stereo input and sound card has two
+; physical input channels.
+;
+; However in case of only using a single input channel (like condenser
+; microphone) only one channel will have any sound, which is often
+; inconvenient for casual use.
+;
+; This config includes mono input options which makes it much more
+; friendly in single input configuration.
+;
+; This config also removes default digital input/output mappings that do
+; not physically exist on this card.
+;
+; Added by Nazar Mokrynskyi <nazar@mokrynskyi.com>
+
+[General]
+auto-profiles = yes
+
+[Mapping analog-stereo-input]
+device-strings = hw:%f
+channel-map = left,right
+paths-input = analog-input-mic
+direction = input
+priority = 4
+
+[Mapping analog-mono]
+device-strings = hw:%f
+channel-map = mono,mono
+paths-input = analog-input-mic
+direction = input
+priority = 3
+
+[Mapping analog-mono-left]
+device-strings = hw:%f
+channel-map = mono,aux1
+paths-input = analog-input-mic
+direction = input
+priority = 2
+
+[Mapping analog-mono-right]
+device-strings = hw:%f
+channel-map = aux1,mono
+paths-input = analog-input-mic
+direction = input
+priority = 1
+
+[Mapping analog-stereo-output]
+device-strings = front:%f
+channel-map = left,right
+paths-output = analog-output
+direction = output