[LAU] anyone running 4.13.15-300.rt5.1.fc27.ccrma.x86_64+rt + snd_usb yet?

Anyone running the 4.13.15-300.rt5.1.fc27.ccrma.x86_64+rt from the PlanetCCRMA repository with a USB audio interface? I find that my USB interface makes output so distorted it is not recognizable with that RT kernel, but works OK with the stock fedora kernel. I find no error messages in /var/log/messages or dmesg when playing audio. I tried aplay, but no error messages at all. I thought perhaps jackd would give useful error messages, but I see no errors when starting, but "no callback" messages begin showing up right away. I'm stopped at the moment, I do not know how to proceed without finding some kind of error message to point me in the right direction. Is there any other location to find status information on USB audio devices? This is the rtirq configuration in use: RTIRQ_NAME_LIST="usb enp3s4f1 i8042" RTIRQ_PRIO_HIGH=95 RTIRQ_PRIO_DECR=2 Is "usb" enough there, or should it be snd_usb in place of usb? As an aside, I found that the IRQ priorities were not set automatically, I had to manually run rtirq, but that is probably a fedora package problem. Getting USB interrupt priority set to a high priority made no difference This is the startup output from jackd: Acquire audio card Audio1 creating alsa driver ... hw:Lambda|hw:Lambda|1024|3|48000|0|0|nomon|swmeter|-|32bit configuring for 48000Hz, period = 1024 frames (21.3 ms), buffer = 3 periods ALSA: final selected sample format for capture: 24bit little-endian ALSA: use 3 periods for capture ALSA: final selected sample format for playback: 24bit little-endian ALSA: use 3 periods for playback Jack: JackSocketServerChannel::Open Jack: JackServerSocket::Bind : addr.sun_path /dev/shm/jack_default_1000_0 Jack: JackSocketServerChannel::BuildPoolTable size = 1 Jack: JackEngine::Open Jack: JackClientSocket::Connect : addr.sun_path /dev/shm/jack_default_1000_0 Jack: JackEngine::ClientInternalOpen: name = freewheel Jack: JackEngine::AllocateRefNum ref = 1 Jack: JackPosixSemaphore::Allocate name = jack_sem.1000_default_freewheel val = 0 Jack: JackEngine::NotifyAddClient: name = freewheel Jack: JackDriver::ClientNotify ref = 1 driver = system name = freewheel notify = 0 Jack: JackDriver::ClientNotify ref = 0 driver = freewheel name = system notify = 0 Jack: JackConnectionManager::DirectConnect first: ref1 = 1 ref2 = 1 Jack: JackGraphManager::ConnectRefNum cur_index = 0 ref1 = 1 ref2 = 1 Jack: JackDriver::SetupDriverSync driver sem in flush mode Jack: JackGraphManager::SetBufferSize size = 1024 Jack: JackAlsaDriver::Attach fBufferSize 1024 fSampleRate 48000 Using port names patch v0.1 (07.04.2010) Trying to load portnames from /home/chris/.config/jack/cards/Lexicon Lambda.ss.ports.in Trying to load portnames from /home/chris/.config/jack/cards/Lexicon Lambda.ports.in Trying to load portnames from /etc/jack/cards/Lexicon Lambda.ss.ports.in Trying to load portnames from /etc/jack/cards/Lexicon Lambda.ports.in Trying to load portnames from /home/chris/.config/jack/cards/Lexicon Lambda.ss.ports.out Trying to load portnames from /home/chris/.config/jack/cards/Lexicon Lambda.ports.out Trying to load portnames from /etc/jack/cards/Lexicon Lambda.ss.ports.out Trying to load portnames from /etc/jack/cards/Lexicon Lambda.ports.out Jack: JackEngine::PortRegister ref = 0 name = system:capture_1 type = 32 bit float mono audio flags = 22 buffer_size = 1024 Jack: JackGraphManager::AllocatePortAux port_index = 1 name = system:capture_1 type = 32 bit float mono audio Jack: JackConnectionManager::AddOutputPort ref = 0 port = 1 Jack: JackEngine::ClientNotify: no callback for notification = 9 Jack: JackEngine::ClientNotify: no callback for notification = 9 Jack: JackAlsaDriver::Attach fCapturePortList[i] 1 Jack: JackEngine::PortRegister ref = 0 name = system:capture_2 type = 32 bit float mono audio flags = 22 buffer_size = 1024 Jack: JackGraphManager::AllocatePortAux port_index = 2 name = system:capture_2 type = 32 bit float mono audio Jack: JackConnectionManager::AddOutputPort ref = 0 port = 2 Jack: JackEngine::ClientNotify: no callback for notification = 9 Jack: JackEngine::ClientNotify: no callback for notification = 9 Jack: JackAlsaDriver::Attach fCapturePortList[i] 2 Jack: JackEngine::PortRegister ref = 0 name = system:playback_1 type = 32 bit float mono audio flags = 21 buffer_size = 1024 Jack: JackGraphManager::AllocatePortAux port_index = 3 name = system:playback_1 type = 32 bit float mono audio Jack: JackConnectionManager::AddInputPort ref = 0 port = 3 Jack: JackEngine::ClientNotify: no callback for notification = 9 Jack: JackEngine::ClientNotify: no callback for notification = 9 -- Chris Caudle