Hi,
I use Echo Audiofire Pre 8 and worried about JACK's rondom XRUN.
Fortunately I have a friend who is Linux-based system engineer and ask
him this issue. Then he gave me two solutions.
1. see IRQ in /proc/interrupts
2. use HPET as system clock source
IRQ have a various meanings but in this case it means device
input/output. you can see IRQ with the command 'cat /proc/interrupts'.
Example below,
$ cat /proc/interrupts;
CPU0 CPU1 CPU2 CPU3
0: 6206090 0 0 0 IO-APIC-edge timer
1: 2 0 0 0 IO-APIC-edge i8042
8: 1 0 0 0 IO-APIC-edge rtc0
9: 0 0 0 0 IO-APIC-fasteoi acpi
12: 4 0 0 0 IO-APIC-edge i8042
16: 95779 0 0 0 IO-APIC-fasteoi
uhci_hcd:usb3, pata_jmicron, nvidia
17: 0 0 0 0 IO-APIC-fasteoi ahci
18: 21 74 0 0 IO-APIC-fasteoi
ehci_hcd:usb1, uhci_hcd:usb5, uhci_hcd:usb8, pata_jmicron, firewire_ohci
19: 0 0 0 0 IO-APIC-fasteoi
uhci_hcd:usb7, ahci
21: 36 0 0 0 IO-APIC-fasteoi
uhci_hcd:usb4
23: 26 0 0 0 IO-APIC-fasteoi
ehci_hcd:usb2, uhci_hcd:usb6
Your firewire device is driven by firewire_ohci and you can see how many
interrupts happen in the layer including firewire_ohci. In this example,
you can see uhci_hcd:usb5 or uhci_hcd:usb8 in the same layer. If I
connect my USB mouse or keyboard to uhci_hcd:usb5 or uhci_hcd:usb8, the
interrupt from Firewire device happens every time I use USB devices. I
guess this causes FFADO XRUNs.
So in this case you can change the port of USB devices looking
/proc/interrupts and seek the port disrelated to firewire_ohci.
I seldom get FFADO's XRUN with HPET clock source but I have no idea of
technical differences of TSC and HPET...You can change the clocksource
in your kernel option.
Regards
Takashi Sakamoto
o-taka...@sakamocchi.jp
(2011年06月05日 17:24), bart deruyter wrote:
Hi all,
since recently I'm experiencing more xruns in ubuntustudio 11.04, more
specifically using the lowlatency kernel. My audiocard is an external
one, firewire, and I use the firewire driver. They just started
happening out of the blue, without changing anything significantly.
These xruns happen randomly, not caused by anything I do on the desktop.
When I keep qjackctl running without any audio apps open, now and then,
about each half hour, or 20 minutes, there is an xrun.
My limits.conf file seems to be as described on the wiki's over the web,
I have 4 GB or ram, a duocore processor.. I see no reason for problems.
I've got a latency of 17.4 msec, with a setting of 256 Frames/Perios,
Sample Rate of 44100, and 3 Periods/Buffer. So far this was the most
stable setup, though I'm sure I should be able to go to 128
Frames/Period with my AudioFire12. But I can't, more xruns happen when
using this setting. Setting the samplerate higher I get more xruns too.
I'd love to record on 96000, or even 192000, which is possible with the
audiocard, but the computer system prevents this because of these xruns.
This does make it unreliable for recording, which I want to do more
regularly and it makes me impossible to do recordings for others. I do
not want a system where I have to ask people to start playing again for
the recording because xruns.
So, I was wondering, are there diagnostic tools, test scrips, tracing
tools to get me to the bottom of this?
Grtz,
Bart
http://www.bartart3d.be/
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