Hello, I'm quite a bit puzzled and so I'm hoping to find something I haven't considered yet. I'm using a FireWire Saffire LE Audio Interface, connected to the following PCI card: NEC Corporation uPD72873 [Firewarden] IEEE1394a OHCI 1.1 Link/2-port PHY Controller (rev 01). Software information: ffado built from svn, jack 1.9.8, kernel 3.5.3 PREEMT (no realtime patch) or 3.4.9-rt17 (with realtime patch), libraw 2.1.0. No matter what I configure jack to run with, I get regular xruns every few seconds whilst doing nothing. The last settings I tried were: Frames/Period: 4096 Sample Rate: 96000 Periods/Buffer: 3 (Latency: 128ms) And still no avail, results are like this, just after starting, without actually doing anything: 19:02:48.093 XRUN callback (1). 19:03:03.002 XRUN callback (2). 19:03:05.713 XRUN callback (3). 19:03:08.257 XRUN callback (4). 19:03:12.160 XRUN callback (5). Interrupt information: 21: 0 1 1 33 1087 339542 IO-APIC-fasteoi firewire_ohci Things I tried: Basically everything suggested by the realTimeConfigQuickScan tool, like changing CPU governor to "performance" or decreasing swappiness. I am member of the "audio" groups, which has the following permissions, as per limits.conf: @audio - rtprio 99 @audio - memlock 8388608 @audio - nice -5 /dev/rtc and /dev/hpet are both read- and writeable by group "audio". # /etc/init.d/rtirq status PID CLS RTPRIO NI PRI %CPU STAT COMMAND 1075 FF 90 - 130 0.0 S irq/8-rtc0 1407 FF 85 - 125 0.4 S irq/21-firewire 1063 FF 80 - 120 0.0 S irq/1-i8042 [...] Any advice on what I could be missing? The same system was working some time ago, so I really don't know what I did wrong this time. For even further information, below is the output of ffado-diag: many thanks, Sebastian $ ffado-diag FFADO diagnostic utility 2.999.0-Unversioned directory ============================ (C) 2008 Pieter Palmers 2009-2010 Arnold Krille === CHECK === Base system... kernel version............ 3.5.3-gentoo Preempt (low latency)... True RT patched.............. False old 1394 stack present.... False old 1394 stack loaded..... False old 1394 stack active..... False new 1394 stack present.... True new 1394 stack loaded..... True new 1394 stack active..... True /dev/raw1394 node present. False /dev/fw* permissions: crw------- 1 root root 248, 0 Sep 14 18:14 /dev/fw0 crw-rw----+ 1 root audio 248, 1 Sep 14 18:25 /dev/fw1 User IDs: uid=1000(rose) gid=10(wheel) groups=10(wheel),4(adm),5(tty),6(disk),7(lp),14(uucp),16(cron),18(audio),19(cdrom),27(video),81(apache),85(usb),100(users),102(davfs2),250(portage),407(crontab),1001(games),1002(plugdev),1010(kvm) Prerequisites (dynamic at run-time)... gcc ............... gcc (Gentoo 4.6.3 p1.6, pie-0.5.2) 4.6.3 g++ ............... g++ (Gentoo 4.6.3 p1.6, pie-0.5.2) 4.6.3 PyQt4 (by pyuic4) . Python User Interface Compiler 4.9.4 for Qt version 4.8.2 jackd ............. no message buffer overruns path ............ /usr/bin/jackd flags ........... -L/usr/lib -ljack libraw1394 ........ 2.1.0 flags ........... -lraw1394 libavc1394 ........ 0.5.4 flags ........... -lavc1394 -lrom1394 -lraw1394 libiec61883 ....... 1.1.0 flags ........... -liec61883 -lraw1394 libxml++-2.6 ...... 2.34.2 flags ........... -I/usr/include/libxml++-2.6 -I/usr/lib64/libxml++-2.6/include -I/usr/include/libxml2 -I/usr/include/glibmm-2.4 -I/usr/lib64/glibmm-2.4/include -I/usr/include/sigc++-2.0 -I/usr/lib64/sigc++-2.0/include -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -lxml++-2.6 -lxml2 -lglibmm-2.4 -lgobject-2.0 -lsigc-2.0 -lglib-2.0 dbus-1 ............ 1.6.4 flags ........... -I/usr/include/dbus-1.0 -I/usr/lib64/dbus-1.0/include -ldbus-1 Prerequisites (static at compile-time)... gcc ............... gcc (Gentoo 4.6.3 p1.6, pie-0.5.2) 4.6.3 g++ ............... g++ (Gentoo 4.6.3 p1.6, pie-0.5.2) 4.6.3 PyQt4 (by pyuic4) . Python User Interface Compiler 4.9.4 for Qt version 4.8.2 jackd ............. no message buffer overruns path ............ /usr/bin/jackd flags ........... -L/usr/lib -ljack libraw1394 ........ 2.1.0 flags ........... -lraw1394 libavc1394 ........ 0.5.4 flags ........... -lavc1394 -lrom1394 -lraw1394 libiec61883 ....... 1.1.0 flags ........... -liec61883 -lraw1394 libxml++-2.6 ...... 2.34.2 flags ........... -I/usr/include/libxml++-2.6 -I/usr/lib64/libxml++-2.6/include -I/usr/include/libxml2 -I/usr/include/glibmm-2.4 -I/usr/lib64/glibmm-2.4/include -I/usr/include/sigc++-2.0 -I/usr/lib64/sigc++-2.0/include -I/usr/include/glib-2.0 -I/usr/lib64/glib-2.0/include -lxml++-2.6 -lxml2 -lglibmm-2.4 -lgobject-2.0 -lsigc-2.0 -lglib-2.0 dbus-1 ............ 1.6.4 flags ........... -I/usr/include/dbus-1.0 -I/usr/lib64/dbus-1.0/include -ldbus-1 uname -a... Linux semkath-desktop 3.5.3-gentoo #2 SMP PREEMPT Fri Sep 14 10:13:08 CEST 2012 x86_64 AMD Phenom(tm) II X6 1090T Processor AuthenticAMD GNU/Linux Hardware... Host controllers: 04:06.0 FireWire (IEEE 1394) [0c00]: NEC Corporation uPD72873 [Firewarden] IEEE1394a OHCI 1.1 Link/2-port PHY Controller [1033:00e7] (rev 01) (prog-if 10 [OHCI]) Subsystem: NEC Corporation uPD72873 [Firewarden] IEEE1394a OHCI 1.1 Link/2-port PHY Controller [1033:00e7] Control: I/O- Mem+ BusMaster+ SpecCycle- MemWINV+ VGASnoop- ParErr- Stepping- SERR+ FastB2B- DisINTx- Status: Cap+ 66MHz- UDF- FastB2B+ ParErr- DEVSEL=medium Latency: 32 (5000ns min, 11000ns max), Cache Line Size: 64 bytes Interrupt: pin A routed to IRQ 21 Region 0: Memory at fe9fe000 (32-bit, non-prefetchable) [size=4K] Capabilities: <access denied> Kernel driver in use: firewire_ohci CPU info: Architecture: x86_64 CPU op-mode(s): 32-bit, 64-bit Byte Order: Little Endian CPU(s): 6 On-line CPU(s) list: 0-5 Thread(s) per core: 1 Core(s) per socket: 6 Socket(s): 1 NUMA node(s): 1 Vendor ID: AuthenticAMD CPU family: 16 Model: 10 Stepping: 0 CPU MHz: 3200.000 BogoMIPS: 6412.71 Virtualization: AMD-V L1d cache: 64K L1i cache: 64K L2 cache: 512K L3 cache: 6144K NUMA node0 CPU(s): 0-5