On E-MU 0204 USB only 2-channel mode worked. In this mode the second pair of channels just duplicates the output of the first pair. Under windows E-MU control panel allow to switch to 2-channel or 4-channel mode. I ran USB sniffer, and it shows switch commands that the system send to the device:
======================================
Host send 2 bytes to device:
Request: 0x1
Value: 0x400
Data: 01 01 //switching to 2-channel mode
Data: 01 02 //switching to 4-channel mode
======================================
Looks like in Ubuntu the card by default stay in 2-channel mode. Switching to 4-channel mode apparently can be added to quirks.c
On E-MU 0204 USB only 2-channel mode worked. In this mode the second pair of channels just duplicates the output of the first pair. Under windows E-MU control panel allow to switch to 2-channel or 4-channel mode. I ran USB sniffer, and it shows switch commands that the system send to the device:
======= ======= ======= ======= ======= === ======= ======= ======= ======= ===
Host send 2 bytes to device:
Request: 0x1
Value: 0x400
Data: 01 01 //switching to 2-channel mode
Data: 01 02 //switching to 4-channel mode
=======
Looks like in Ubuntu the card by default stay in 2-channel mode. Switching to 4-channel mode apparently can be added to quirks.c
DistroRelease: Ubuntu 12.10 dfsg-0ubuntu4 generic x86_64
Package: alsa-base 1.0.25+
Uname: Linux 3.9.6-030906-
Architecture: amd64