Hi :) this is very strange. A regular kernel doesn't cause xruns, but a kernel-rt does always cause xruns, when running jack_midi_latency_test. Because the proprietary nvidia driver doesn't work on my machine, when using a kernel-rt, what ever trick I try, I tested the nouveau driver. The nouveau driver does cause xruns for my RME card, but is ok with a TerraTec card. I switched to the nv driver and still get xruns for the RME card and the TerraTec card completely fails the test using a kernel-rt. When I repeat the test with a regular kernel, while using the proprietary nvidia driver, the RME card passes the test without xruns and the TerraTec card also is ok. The only idea I've got is to compile a full preempt kernel, boot it with threadirqs and to use the proprietary nvidia driver, but I would prefer to use a kernel-rt. Any hints are welcome. Arch Linux x86_64 mouse and iPad connected to USB ports when I started the test I thought the issues could be related to the connected iPad, but they aren't [spinymouse@archlinux ~]$ sudo cpupower frequency-set -g performance [spinymouse@archlinux ~]$ uname -r 3.4.4-rt14-1-rt [spinymouse@archlinux ~]$ hdspmixer Card 0: RME AIO S/N 0x579bcc at 0xfdbf0000, irq 18 Card 1: TerraTec EWX24/96 at 0xbf00, irq 20 Card 2: TerraTec EWX24/96 at 0xbb00, irq 21 [spinymouse@archlinux ~]$ sudo chgrp audio /dev/hpet [spinymouse@archlinux ~]$ sudo chmod g+rw /dev/hpet [spinymouse@archlinux ~]$ sudo modprobe snd-hrtimer [spinymouse@archlinux ~]$ /etc/rc.d/rtirq status PID CLS RTPRIO NI PRI %CPU STAT COMMAND 59 FF 90 - 130 0.0 S irq/8-rtc0 283 FF 85 - 125 0.0 S irq/18-snd_hdsp 320 FF 80 - 120 0.0 S irq/20-snd_ice1 322 FF 79 - 119 0.0 S irq/21-snd_ice1 104 FF 70 - 110 0.0 S irq/19-ehci_hcd 106 FF 70 - 110 0.3 S irq/16-ohci_hcd 108 FF 69 - 109 0.0 S irq/17-ohci_hcd 112 FF 68 - 108 0.0 S irq/17-ohci_hcd 57 FF 65 - 105 0.0 S irq/1-i8042 20 FF 50 - 90 0.0 S irq/9-acpi 92 FF 50 - 90 0.1 S irq/22-ahci 110 FF 50 - 90 0.0 S irq/18-ohci_hcd 114 FF 50 - 90 0.0 S irq/18-ohci_hcd 117 FF 50 - 90 0.0 S irq/14-pata_ati 118 FF 50 - 90 0.0 S irq/15-pata_ati 257 FF 50 - 90 0.0 S irq/7-parport0 270 FF 50 - 90 0.0 S irq/22-firewire 587 FF 50 - 90 0.0 S irq/43-eth0 3 FF 1 - 41 0.0 S ksoftirqd/0 11 FF 1 - 41 0.0 S ksoftirqd/1 [spinymouse@archlinux ~]$ grep Driver /etc/X11/xorg.conf #Driver "nvidia" Driver "nv" #Driver "nouveau" #Driver "vesa" [spinymouse@archlinux ~]$ jackd --sync -Xalsarawmidi -dalsa -r48000 -p256 jackdmp 1.9.8 [spinymouse@archlinux ~]$ jack_midi_latency_test -m 3 -s 8192 -t 5 "system:1-1 HDSPMx579bcc MIDI 1 1 out" "system:1-1 HDSPMx579bcc MIDI 1 1 in" Waiting for connections ... Waiting for test completion ... Reported out-port latency: 5.33-5.33 ms (256-256 frames) Reported in-port latency: 5.33-5.33 ms (256-256 frames) Average latency: 11.67 ms (560.27 frames) Lowest latency: 11.65 ms (559 frames) Highest latency: 11.75 ms (564 frames) Peak MIDI jitter: 0.10 ms (5 frames) Average MIDI jitter: 0.01 ms (0.08 frames) Jitter Plot: 0.0 - 0.1 ms: 8191 > 10 ms: 1 Latency Plot: 11.6 - 11.7 ms: 8091 11.7 - 11.8 ms: 100 > 21.6 ms: 1 Messages sent: 8192 Messages received: 8192 Xruns: 1 computer issues, a reset was needed only mouse connected to an USB port [spinymouse@archlinux ~]$ sudo cpupower frequency-set -g performance [spinymouse@archlinux ~]$ uname -r 3.4.4-rt14-1-rt [spinymouse@archlinux ~]$ hdspmixer Card 0: RME AIO S/N 0x579bcc at 0xfdef0000, irq 18 Card 1: TerraTec EWX24/96 at 0xbf00, irq 20 Card 2: TerraTec EWX24/96 at 0xbb00, irq 21 [spinymouse@archlinux ~]$ sudo chgrp audio /dev/hpet [spinymouse@archlinux ~]$ sudo chmod g+rw /dev/hpet [spinymouse@archlinux ~]$ sudo modprobe snd-hrtimer [spinymouse@archlinux ~]$ /etc/rc.d/rtirq status PID CLS RTPRIO NI PRI %CPU STAT COMMAND 59 FF 90 - 130 0.0 S irq/8-rtc0 361 FF 85 - 125 0.0 S irq/18-snd_hdsp 365 FF 80 - 120 0.0 S irq/20-snd_ice1 368 FF 79 - 119 0.0 S irq/21-snd_ice1 113 FF 70 - 110 0.0 S irq/19-ehci_hcd 115 FF 70 - 110 0.3 S irq/16-ohci_hcd 117 FF 69 - 109 0.0 S irq/17-ohci_hcd 121 FF 68 - 108 0.0 S irq/17-ohci_hcd 57 FF 65 - 105 0.0 S irq/1-i8042 20 FF 50 - 90 0.0 S irq/9-acpi 102 FF 50 - 90 0.2 S irq/22-ahci 119 FF 50 - 90 0.0 S irq/18-ohci_hcd 123 FF 50 - 90 0.0 S irq/18-ohci_hcd 126 FF 50 - 90 0.0 S irq/14-pata_ati 127 FF 50 - 90 0.0 S irq/15-pata_ati 289 FF 50 - 90 0.0 S irq/7-parport0 324 FF 50 - 90 0.0 S irq/22-firewire 618 FF 50 - 90 0.0 S irq/43-eth0 3 FF 1 - 41 0.1 S ksoftirqd/0 11 FF 1 - 41 0.1 S ksoftirqd/1 [spinymouse@archlinux ~]$ grep Driver /etc/X11/xorg.conf #Driver "nvidia" Driver "nv" #Driver "nouveau" #Driver "vesa" [spinymouse@archlinux ~]$ jackd --sync -Xalsarawmidi -dalsa -r48000 -p256 jackdmp 1.9.8 [spinymouse@archlinux ~]$ jack_midi_latency_test -m 3 -s 8192 -t 5 "system:1-1 HDSPMx579bcc MIDI 1 1 out" "system:1-1 HDSPMx579bcc MIDI 1 1 in" Waiting for connections ... Waiting for test completion ... Reported out-port latency: 5.33-5.33 ms (256-256 frames) Reported in-port latency: 5.33-5.33 ms (256-256 frames) Average latency: 11.69 ms (560.56 frames) Lowest latency: 11.64 ms (559 frames) Highest latency: 11.77 ms (565 frames) Peak MIDI jitter: 0.13 ms (6 frames) Average MIDI jitter: 0.02 ms (0.04 frames) Jitter Plot: 0.0 - 0.1 ms: 8187 > 10 ms: 5 Latency Plot: 11.6 - 11.7 ms: 7919 11.7 - 11.8 ms: 268 > 21.6 ms: 5 Messages sent: 8192 Messages received: 8192 Xruns: 5 [spinymouse@archlinux ~]$ jack_midi_latency_test -m 3 -s 8192 -t 5 "system:2-1 TerraTec EWX24/96 MIDI 1 out" "system:2-1 TerraTec EWX24/96 MIDI 1 in" Waiting for connections ... Waiting for test completion ... Messages sent: 5619 Messages received: 5618 jack_midi_latency_test: handle_process: timed out while waiting for MIDI message before I reset the computer I got this too, this time a shutdown was possible I also disconnected the computer from the mains for 55 minutes, before I booted again only mouse connected to an USB port now without hpet enabled [spinymouse@archlinux ~]$ sudo cpupower frequency-set -g performance [spinymouse@archlinux ~]$ uname -r 3.4.4-rt14-1-rt [spinymouse@archlinux ~]$ hdspmixer Card 0: RME AIO S/N 0x579bcc at 0xfdef0000, irq 18 Card 1: TerraTec EWX24/96 at 0xbf00, irq 20 Card 2: TerraTec EWX24/96 at 0xbb00, irq 21 [spinymouse@archlinux ~]$ /etc/rc.d/rtirq status PID CLS RTPRIO NI PRI %CPU STAT COMMAND 59 FF 90 - 130 0.0 S irq/8-rtc0 318 FF 85 - 125 0.0 S irq/18-snd_hdsp 326 FF 80 - 120 0.0 S irq/20-snd_ice1 328 FF 79 - 119 0.0 S irq/21-snd_ice1 107 FF 70 - 110 0.0 S irq/19-ehci_hcd 109 FF 70 - 110 0.2 S irq/16-ohci_hcd 121 FF 69 - 109 0.0 S irq/17-ohci_hcd 125 FF 68 - 108 0.0 S irq/17-ohci_hcd 57 FF 65 - 105 0.0 S irq/1-i8042 20 FF 50 - 90 0.0 S irq/9-acpi 100 FF 50 - 90 0.0 S irq/14-pata_ati 101 FF 50 - 90 0.0 S irq/15-pata_ati 111 FF 50 - 90 0.2 S irq/22-ahci 123 FF 50 - 90 0.0 S irq/18-ohci_hcd 127 FF 50 - 90 0.0 S irq/18-ohci_hcd 279 FF 50 - 90 0.0 S irq/7-parport0 323 FF 50 - 90 0.0 S irq/22-firewire 586 FF 50 - 90 0.0 S irq/43-eth0 3 FF 1 - 41 0.1 S ksoftirqd/0 11 FF 1 - 41 0.1 S ksoftirqd/1 [spinymouse@archlinux ~]$ grep Driver /etc/X11/xorg.conf #Driver "nvidia" Driver "nv" #Driver "nouveau" #Driver "vesa" [spinymouse@archlinux ~]$ jackd --sync -Xalsarawmidi -dalsa -r48000 -p256 jackdmp 1.9.8 [spinymouse@archlinux ~]$ jack_midi_latency_test -m 3 -s 8192 -t 5 "system:1-1 HDSPMx579bcc MIDI 1 1 out" "system:1-1 HDSPMx579bcc MIDI 1 1 in" Waiting for connections ... Waiting for test completion ... Reported out-port latency: 5.33-5.33 ms (256-256 frames) Reported in-port latency: 5.33-5.33 ms (256-256 frames) Average latency: 11.67 ms (560.32 frames) Lowest latency: 11.64 ms (559 frames) Highest latency: 11.75 ms (564 frames) Peak MIDI jitter: 0.11 ms (5 frames) Average MIDI jitter: 0.01 ms (0.09 frames) Jitter Plot: 0.0 - 0.1 ms: 8192 Latency Plot: 11.6 - 11.7 ms: 8024 11.7 - 11.8 ms: 168 Messages sent: 8192 Messages received: 8192 after the test for the TerraTec failed again, I had to reset the computer I booted a kernel-rt for AV Linux unfortunately Jack2 is version 1.9.6, so I booted Arch Linux again, but this time I didn't boot the kernel-rt [spinymouse@archlinux ~]$ sudo cpupower frequency-set -g performance [spinymouse@archlinux ~]$ uname -r 3.5.4-1-ARCH [spinymouse@archlinux ~]$ hdspmixer Card 0: RME AIO S/N 0x579bcc at 0xfdbf0000, irq 18 Card 1: TerraTec EWX24/96 at 0xbf00, irq 20 Card 2: TerraTec EWX24/96 at 0xbb00, irq 21 [spinymouse@archlinux ~]$ /etc/rc.d/rtirq status PID CLS RTPRIO NI PRI %CPU STAT COMMAND 3 TS - 0 19 0.0 S ksoftirqd/0 10 TS - 0 19 0.0 S ksoftirqd/1 [spinymouse@archlinux ~]$ grep Driver /etc/X11/xorg.conf ### Driver "nvidia" #Driver "nv" #Driver "nouveau" #Driver "vesa" spinymouse@archlinux ~]$ jackd --sync -Xalsarawmidi -dalsa -r48000 -p256 jackdmp 1.9.8 [spinymouse@archlinux ~]$ jack_midi_latency_test -m 3 -s 8192 -t 5 "system:2-1 TerraTec EWX24/96 MIDI 1 out" "system:2-1 TerraTec EWX24/96 MIDI 1 in" Waiting for connections ... Waiting for test completion ... Reported out-port latency: 5.33-5.33 ms (256-256 frames) Reported in-port latency: 5.33-5.33 ms (256-256 frames) Average latency: 11.67 ms (560.05 frames) Lowest latency: 11.67 ms (560 frames) Highest latency: 11.77 ms (565 frames) Peak MIDI jitter: 0.11 ms (5 frames) Average MIDI jitter: 0.00 ms (0.01 frames) Jitter Plot: 0.0 - 0.1 ms: 8191 0.1 - 0.2 ms: 1 Latency Plot: 11.6 - 11.7 ms: 8146 11.7 - 11.8 ms: 46 Messages sent: 8192 Messages received: 8192 [spinymouse@archlinux ~]$ jack_midi_latency_test -m 3 -s 8192 -t 5 "system:1-1 HDSPMx579bcc MIDI 1 1 out" "system:1-1 HDSPMx579bcc MIDI 1 1 in" Waiting for connections ... Waiting for test completion ... Reported out-port latency: 5.33-5.33 ms (256-256 frames) Reported in-port latency: 5.33-5.33 ms (256-256 frames) Average latency: 11.68 ms (560.43 frames) Lowest latency: 11.65 ms (559 frames) Highest latency: 11.73 ms (563 frames) Peak MIDI jitter: 0.08 ms (4 frames) Average MIDI jitter: 0.01 ms (0.01 frames) Jitter Plot: 0.0 - 0.1 ms: 8192 Latency Plot: 11.6 - 11.7 ms: 8156 11.7 - 11.8 ms: 36 Messages sent: 8192 Messages received: 8192 Regards, Ralf