UI does not permit configuring usb_stream-based device

[David Kastrup]

I absolutely positively cannot convince the User interface to accept an alsa device usb_stream:US122L . It insists on rewriting this as hw:US122L which has no functioning pcm access.

Starting jackd manually with -d alsa -dusb_stream:US122L is absolutely no problem once ~/.asoundrc is told about this with
# The usb_stream plugin configuration

pcm.!usb_stream {
        @args [ CARD ]
        @args.CARD {
                type string
                default "US122L"
        }
        type usb_stream

        card $CARD
}

ctl.!usb_stream {
        @args [ CARD ]
        @args.CARD {
                type string
                default "US122L"
        }

        type hw

        card $CARD
}

Note that aplay -l will not list the US122L card while aplay -L will list it.

I can enter usb_stream:US122L in the selection menu for the device, but as soon as I press RET, it gets replaced by hw:US122L again. I have not been able to find what to patch in order to be allowed entering this device.