The udev module in PA also detects your coldplugged hardware, it's just a hardware detection layer. It handles hotplugging too. The difference between an USB headset and a p2 (conventional) headphone/headset is that the USB one is detected by the computer (not only by linux/pa/alsa) as a complete new sound card. This new sound card has one input and one output only, both hard-wired to the headphone and microphone in the headset. Jack detection acts like udev hotplug manager, but for physical connections: the sound board is there already, jack is just "something" that watches sound card connection impedances, and switches it's working mode (input or output) depending on what is connected. So PA udev module can't decode that information, PA needs a Jack module to handle that. -------------- next part -------------- An HTML attachment was scrubbed... URL: <http://lists.freedesktop.org/archives/pulseaudio-discuss/attachments/20110720/b069d768/attachment.html>