Hello folks, I use two USB 7.1 sound cards (C-Media chip CM6533 I think) on a Raspi 4. I wanted to split the 8 channel sound cards to have 8 single stereo outputs. For this I wanted to use the ALSA dshare plugin. My problem: I cannot use two virtual sound cards from two different real sound cards at the same time. For better explanation here my asound.conf with a minimal configuration to demonstrate my problem: You can see two sound cards hw:1,0 and hw:2,0. Form card1 I created with dshare stereo1 and from card2 I created stereo2. pcm_slave.card1 { pcm "hw:1,0" channels 8 } pcm.stereo1 { type plug slave.pcm { type dshare ipc_key 1111 slave card1 bindings.0 0 bindings.1 1 } } pcm_slave.card2{ pcm "hw:2,0" channels 8 } pcm.stereo2 { type plug slave.pcm { type dshare ipc_key 2222 slave card2 bindings.0 0 bindings.1 1 } } I cannot playback an audio file via aplay from stereo1 and stereo2 at the same time. If I have started the playback from stereo1 and then want to start the playback from stereo2 I get the following error: pi@raspberrypi:~ $ aplay -Dplug:stereo2 /var/lib/mpd/music/example.mp3 ALSA lib pcm_direct.c:1271:(snd1_pcm_direct_initialize_slave) unable to install hw params ALSA lib pcm_dshare.c:778:(snd_pcm_dshare_open) unable to initialize slave aplay: main:828: audio open error: Input/output error Please can anyone help me. I have no clue how to solve this. Actually, this setup worked before with an BeagleBoneBlack with an old Ubuntu. I have no idea why this should not work with my Raspi 4. Here is my output of alsa-info: http://alsa-project.org/db/?f=754e988bd2b94cd4679060d1fa7d19c87b1d0077 Thanks in advance. Best wishes, Andreas |
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