It's currently not possible to specify one
specific ALSA
device in a pipeline such that the same pipeline is guaranteed to
work across machine reboots. The problem is that ALSA card numbers
are generated on each system startup. The result depends on the
random order of which kernel module gets loaded first. When
hotplugging USB audio devices, the card number changes may even
happen without machine reboots.
what about indexing the cards in modules.conf? Works great for me even
when hotplugging USB devices (and I use 5 of them ;-)
Best regards
ce