[PlanetCCRMA] jackd xruns problem: solved? (FC22.6.7rc4O7kernel)

[Fernando Pablo Lopez-Lezcano]

On Sun, 2004-08-15 at 15:04, Arthur Sosa wrote:
> On Sun, 15 Aug 2004 22:56:45 +0200
> Arthur Sosa <arthur.sosa@email.it> wrote:
> 
> >  Oh, oh! You told about video card... arghh! I'll suddendly remove the S3...
> 
> Something changed... bad! Now I have xruns > 5 msecs.
> So do you think the problem could be the nVidia card?
> At the moment I'm not using 3D hardware accelaration,
> so I have not the nVidia drivers installed.
> 
> Are there any tricky way to trace this problem?
> Please be patient, as you noticed I'm not guru-skilled ;-)
> 
> My log messages after # jackd -Rv -d alsa -p 1024 -n 3 -r 44100:

The output from "dmesg" may be better (if you enabled xrun tracing in
alsa), that will include messages from alsa itself). 

> This is   cat /proc/interrupts:
>            CPU0
>   0:    1399455          XT-PIC  timer
>   1:       1990          XT-PIC  i8042
>   2:          0          XT-PIC  cascade
>   8:          1          XT-PIC  rtc
>   9:          0          XT-PIC  acpi
>  10:      31860          XT-PIC  uhci_hcd, uhci_hcd, ohci1394
>  11:       5847          XT-PIC  ehci_hcd, uhci_hcd, VIA8233, eth0
>  12:         58          XT-PIC  i8042
>  14:      23499          XT-PIC  ide0
>  15:      90707          XT-PIC  ide1
> NMI:          0
> ERR:          0

Looks ok. 

> here I  attach the lspci -v output:
> 
> 00:00.0 Host bridge: VIA Technologies, Inc. VT8377 [KT400/KT600 AGP] Host Bridge
>         Subsystem: Giga-byte Technology GA-7VAX Mainboard
>         Flags: bus master, 66Mhz, medium devsel, latency 8

"latency 8" sounds like an absurdly low value but maybe it is fine for
your hardware. Do you see correlation of your xruns with any activity
(for example "moving the mouse causes an xrun"). Hmmm, I don't know much
about pci but this one seems to be the agp bridge, that is, what
connects the processor to the video card (I assume it is agp). A value
of 8 would mean that the video card would have to release the bus very
very often...

>         Memory at d0000000 (32-bit, prefetchable)
>         Capabilities: [a0] AGP version 2.0
>         Capabilities: [c0] Power Management version 2
> 
> 00:01.0 PCI bridge: VIA Technologies, Inc. VT8235 PCI Bridge (prog-if 00 [Normal decode])
>         Flags: bus master, 66Mhz, medium devsel, latency 0
>         Bus: primary=00, secondary=01, subordinate=01, sec-latency=0
>         Memory behind bridge: e8000000-e9ffffff
>         Prefetchable memory behind bridge: d8000000-e7ffffff
>         Capabilities: [80] Power Management version 2
> 
> 00:10.0 USB Controller: VIA Technologies, Inc. VT82xxxxx UHCI USB 1.1 Controller (rev 80) (prog-if 00 [UHCI])
>         Subsystem: Giga-byte Technology GA-7VAX Mainboard
>         Flags: bus master, medium devsel, latency 32, IRQ 10

Again, latency 32 is sort of low. 

For details on what the pci latency is see:
  http://www-106.ibm.com/developerworks/library/l-hw2.html
I would try setting the latencies to something like 64 to see if that
makes a difference. Not all of the pci devices will have settable
latencies. 

-- Fernando