Fernando Lopez-Lezcano a écrit : 
On Tue, 2008-01-22 at 13:29 +0100, hitmuri@no-log.org wrote:
  
Thanks for answering (maybe i could have asked on the linuxmao.org forum
too ;) ) .

I tried to change the rtirq script but it doesn't seem to make any
difference. But while looking at the rt priorities, i noticed that the
highest priority for usb was given to the irq 16 and cat /proc/interrupts
tells me that on irq 16 there's uhci_hcd:usb3 and NVIDIA !!!
When i plug my usb soundcard , it's always on irq 20.
So it looks like the highest priority is given to the graphics card .
    

Because it shares the interrupt with the usb controller which may have
an audio card attached...

What do you see in "cat /proc/interrupts" for other interrupts? Do you
perhaps have another usb controller that does not share an interrupt
with the graphics controller?
cat /proc/interrupts gives me this :
           CPU0       CPU1      
  0:      89731      89923   IO-APIC-edge      timer
  1:        151        113   IO-APIC-edge      i8042
  8:          0          0   IO-APIC-edge      rtc0
  9:         12         11   IO-APIC-fasteoi   acpi
 12:      42277      41891   IO-APIC-edge      i8042
 14:       7056       7085   IO-APIC-edge      libata
 15:       1376       2002   IO-APIC-edge      libata
 16:      11532      11641   IO-APIC-fasteoi   uhci_hcd:usb3, nvidia
 18:          0          0   IO-APIC-fasteoi   yenta
 19:      18782      18903   IO-APIC-fasteoi   ehci_hcd:usb1, uhci_hcd:usb7
 20:       8615       8284   IO-APIC-fasteoi   ehci_hcd:usb2, uhci_hcd:usb5
 21:          1          2   IO-APIC-fasteoi   uhci_hcd:usb4, ohci1394
 22:          0          0   IO-APIC-fasteoi   uhci_hcd:usb6
 23:          0          0   IO-APIC-fasteoi   sdhci:slot0
220:      18041      18081   PCI-MSI-edge      eth0
NMI:          0          0
LOC:      92078      94169
ERR:          0
MIS:          0


Actually the usb controller on which my soundcard is (IRQ 20) isn"t shared with the graphics controller.
So i tried to set the priorities of the other irq so that the usb controller with my soundcard gets the highest priority

I get this with /etc/init.d/rtirq status :
 1047 FF      95   - 135  0.0 S<   IRQ-8        rtc0
  417 FF      88   - 128  0.6 S<   IRQ-20       ehci_hcd:usb2, uhci_hcd:usb5
  425 FF      87   - 127  0.0 S<   IRQ-21       uhci_hcd:usb4, ohci1394
  426 FF      86   - 126  0.0 S<   IRQ-22       uhci_hcd:usb6
    5 FF      50   -  90  0.0 S<   softirq-high/0
    6 FF      50   -  90  0.1 S<   softirq-timer/0
    7 FF      50   -  90  0.0 S<   softirq-net-tx/
    8 FF      50   -  90  0.0 S<   softirq-net-rx/
    9 FF      50   -  90  0.0 S<   softirq-block/0
   10 FF      50   -  90  0.3 S<   softirq-tasklet
   11 FF      50   -  90  0.0 S<   softirq-sched/0
   12 FF      50   -  90  0.0 S<   softirq-hrtimer
   13 FF      50   -  90  0.0 S<   softirq-rcu/0
   18 FF      50   -  90  0.0 S<   softirq-high/1
   19 FF      50   -  90  0.0 S<   softirq-timer/1
   20 FF      50   -  90  0.0 S<   softirq-net-tx/
   21 FF      50   -  90  0.0 S<   softirq-net-rx/
   22 FF      50   -  90  0.0 S<   softirq-block/1
   23 FF      50   -  90  0.0 S<   softirq-tasklet
   24 FF      50   -  90  0.0 S<   softirq-sched/1
   25 FF      50   -  90  0.0 S<   softirq-hrtimer
   26 FF      50   -  90  0.0 S<   softirq-rcu/1
   78 FF      50   -  90  0.0 S<   IRQ-9        acpi
  388 FF      50   -  90  0.0 S<   IRQ-18       yenta
  394 FF      50   -  90  0.1 S<   IRQ-12       i8042
  395 FF      50   -  90  0.0 S<   IRQ-1        i8042
  454 FF      50   -  90  0.1 S<   IRQ-14       libata
  455 FF      50   -  90  0.0 S<   IRQ-15       libata
 1032 FF      50   -  90  0.3 S<   IRQ-220      PCI-MSI-edge      eth0
 1093 FF      50   -  90  0.0 S<   IRQ-23       sdhci:slot0
  416 FF      35   -  75  0.1 S<   IRQ-19       ehci_hcd:usb1, uhci_hcd:usb7
  424 FF      35   -  75  0.3 S<   IRQ-16       uhci_hcd:usb3, nvidia

But it doesn't make any changes, still xruns.

Don't know what to do now, but at least i think i've understood new things on that sound latency and irq priorities stuff ;) .


Flo





  

    
Is this the problem to solve ?
    

  

  

It may be, hard to know for shure. 

-- Fernando


  

  

    

      
2008/1/22, hitmuri@no-log.org <hitmuri@no-log.org>:
      

      

        
Hi everyone,

i have posted this on the planet ccrma list before, but i don't think
it's
a distribution problem. I get xruns when using a m-audio fast track pro
usb soundcard  at 44100Hz, frames/period=64 (same with 128, i need low
latency) ,periods/buffer=2 with my new laptop when i have for example
freewheeling, tapeutape and jack-rack running (xruns seem to appear when
the dsp load rises, i've got none when using tapeutape alone for
example).
Some of them were related to the latest ccrma kernel, and they
disappeared
with a previous one. For the other ones, i have 4 ideas :

1) latency timer :
doing lspci, all the latencies show 0 , even when i set them to antoher
value with setpci. But with dmesg, i can see that at startup they are
set
to 64.
Fernando Lopez-Lezcano told me that on some hardware latency timer
couldn't be changed and that 64 could be enough actually.
(forgot to say that the usb irq isn't shared)

So it looks like i can't do anything for that.

2) rtc :
At startup i have a message from udev : Node Symlink... node /dev/rtc
already exists , link to /dev/rtc0 will not overwrite it.
        

      

      

I got this message too, but I don't know if there is any impact on the
sound
system.

3) soundcard power
      

      

        
The fast track pro can be powered by usb or by an external power supply.
Mine is usb powered for now. Is this a problem ?

4) rtirq
I noticed that in the rtirq script , i have these lines:
RTIRQ_NAME_LIST="rtc snd usb i8042"
RTIRQ_NON_THREADED="rtc snd"
Do they need to be changed when using a usb soundcard ?
        

      

      
If your sound card works with USB, you can write this :

RTIRQ_NAME_LIST="rtc usb i8042"
RTIRQ_NON_THREADED="rtc usb"


Then you restart the script  and echo his status

$ sudo /etc/init.d/rtirq restart
$ /etc/init.d/rtirq status

You will see the priority on each IRQ. Then you have to connect your sound
card on the USB port wich has the best priority.


If anyone has an idea on that...
      

      

        
Sorry it was quite long !!

Thanks

Flo
        

      

      
Hope this help you,
cheers,

Mysth-R


--
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*
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