Due to lack of bandwith with my internal USB bus, like we are discussing in another thread, I ordered a Trust SuperSpeed 2 Port USB 3.0 Laptop Express Card. $ lsusb -v ... 1a:00.0 USB Controller: NEC Corporation Device 0194 (rev 03) (prog-if 30) Subsystem: NEC Corporation Device 0194 Flags: bus master, fast devsel, latency 0, IRQ 16 Memory at f0600000 (64-bit, non-prefetchable) [size=8K] Capabilities:<access denied> Kernel driver in use: xhci_hcd Kernel modules: xhci ... $ lsusb Bus 003 Device 002: ID 0582:00e6 Roland Corp. Bus 003 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 001 Device 003: ID 0c45:6406 Microdia Bus 001 Device 002: ID 8087:0020 Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 002 Device 003: ID 045e:0084 Microsoft Corp. Basic Optical Mouse Bus 002 Device 002: ID 8087:0020 Bus 002 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub I have a new USB bus, and my Edirol UA25-EX is the only device working in bus #3 $ cat /proc/asound/cards 0 [Intel ]: HDA-Intel - HDA Intel HDA Intel at 0xf0a00000 irq 22 1 [Generic ]: HDA-Intel - HD-Audio Generic HD-Audio Generic at 0xcfedc000 irq 17 2 [UA25EX ]: USB-Audio - UA-25EX EDIROL UA-25EX at usb-0000:1a:00.0-3, full speed $ cat /proc/interrupts | grep usb 16: 91 84 83 88 IO-APIC-fasteoi ehci_hcd:usb1, ohci1394, xhci_hcd:usb3 23: 10112 40 2241 34 IO-APIC-fasteoi ehci_hcd:usb2 I have my device working on IRQ 16. everything seems all right, so I start JACK, and I have this error. --- $ /usr/bin/jackd -p1024 -t2000 -dalsa -dhw:2,0 -r44100 -p256 -n2 -Xraw jackd 0.118.0 Copyright 2001-2009 Paul Davis, Stephane Letz, Jack O'Quinn, Torben Hohn and others. jackd comes with ABSOLUTELY NO WARRANTY This is free software, and you are welcome to redistribute it under certain conditions; see the file COPYING for details Memory locking is unlimited - this is dangerous. You should probably alter the line: @audio - memlock unlimited in your /etc/limits.conf to read: @audio - memlock 2937420 no message buffer overruns JACK compiled with System V SHM support. loading driver .. SSE2 detected apparent rate = 44100 creating alsa driver ... hw:2,0|hw:2,0|256|2|44100|0|0|nomon|swmeter|-|32bit control device hw:2 configuring for 44100Hz, period = 256 frames (5.8 ms), buffer = 2 periods ALSA: final selected sample format for capture: 24bit little-endian ALSA: use 2 periods for capture ALSA: final selected sample format for playback: 24bit little-endian ALSA: use 2 periods for playback ALSA: cannot set hardware parameters for playback ALSA: cannot configure playback channel cannot load driver module alsa --- I suppose that the problem is not JACK related, is ALSA related: $ aplay -v -D plughw:UA25EX /usr/share/sounds/alsa/Front_Left.wav Playing WAVE '/usr/share/sounds/alsa/Front_Left.wav' : Signed 16 bit Little Endian, Rate 48000 Hz, Mono aplay: set_params:1053: Unable to install hw params: ACCESS: RW_INTERLEAVED FORMAT: S16_LE SUBFORMAT: STD SAMPLE_BITS: 16 FRAME_BITS: 16 CHANNELS: 1 RATE: 48000 PERIOD_TIME: (125011 125012) PERIOD_SIZE: [6000 6000] PERIOD_BYTES: (12000 12002) PERIODS: (3 4) BUFFER_TIME: 500000 BUFFER_SIZE: 24000 BUFFER_BYTES: 48000 TICK_TIME: 0 Another thing: the device is listed in $ cat /proc/bus/pci/devices | grep xhci and not in $ cat /proc/bus/usb/devices Aany ideas? Thanks in advance, Joan Quintana