On Sat, 3 Nov 2012 01:19:53 +0100
ttoine <[email protected]> wrote:

> Ralf,
> 
> If you don't need restricted drivers, -rt kernel is better than the
> -lowlatency. For audio, and for midi. If you need the restricted
> driver of, for example, nvidia or amd/ati graphic cards, -rt may not
> work. That's why there is the -lowlatency kernel.
> 
> Toine

Hi Toine :)

yes, but I'm mistaken regarding to the issues on my machine. Randomly
the kernel-rt worked better for a while, but now I get xruns again too.
Seemingly sharing IRQs with a sound card is absolutely bad.

On Sat, 03 Nov 2012 01:30:40 +0100
"Kaj Ailomaa" <[email protected]> wrote:

> Did you compare with a lowlatency of the same kernel version?
> If not, the test is not very conclusive.
> 
> If you like to see some good results from a lowlatency kernel, try
> 2.6.37, and perhaps also 2.6.38 and 2.6.39

Hi Kaj :)

with kernels < 2.6.39 (ALSA < 1.0.24) my card doesn't work and for 2.6
kernels at least the rtirq confg needs to be rewritten.

On Sat, 3 Nov 2012 01:43:58 +0100
ttoine <[email protected]> wrote:

> I am running 3.5.0.17 -lowlatency, I think from KXstudio repositories.
> Works great with Ubuntu 12.10.

It's the default kernel for Ubuntu Studio Quantal.

On Sat, 3 Nov 2012 09:45:06 +0800
Ho Wan Chan <[email protected]> wrote:

> -lowlatency kernels aren't from KXStudio, it is in the official Ubuntu
> repositories, and we include it in our live images. Andy Whitcroft of
> Canonical is the main maintainer of the -lowlatency kernels, though I
> think our kernel team (mainly zequence) wants to maintain the precise
> kernels.
> 
> -rt kernels are from the KXStudio repos. However I use -lowlatency
> kernel 3.5.0.17, and it works great.

Hi Ho :)

or we build our kernels simply ourself, see attachment.

Hi Len :)

you're right, but at the moment I use the RME HDSPe without ADAT, just
for a small audio sessions. Because I still get xruns using the
kernel-rt I guess I'm lost. There seems to be nothing I can do against
a shared IRQ. The current issue perhaps isn't caused by Linux, but by
my motherboard.

On Fri, 2 Nov 2012 21:56:36 -0700
"Len Ovens" <[email protected]> wrote:
> Correct me if I am wrong, but are you not running two M-audio cards
> for midi as well? I think if I remember right, they are ice1712
> cards. Does the midi part of it need the ice1712 kernel driver? That
> is, would you still get midi if the ice1712 driver was black listed
> or unloaded? I'm just wondering if ALSA is using cpu time servicing
> 20 inputs at 48000 hrz for something you are not using. (24bits of
> silence is still 24 bits of throughput and the ice chips are 10
> channels each) I don't know how ALSA handles unused (unconnected)
> ports. I do know that jack and pulse take just as much time dealing
> with all the ports even the ones you don't happen to be using.

Two TerraTec EWX 24/96, but they are Envy24 too. A good idea. Btw. top
doesn't show the ATI graphics when running the MIDI/audio session.
The ATI graphics shares the IRQ with the RME. Some ohci device very
often is shown. Since nothing else is connected to USB at the moment,
it must be the mouse. I'll connect it to another USB port. Right now
I'm not using the TerraTec cards, removing the module on the quick
doesn't work:

spinymouse@qrc:~$ sudo rmmod snd-ice1712
spinymouse@qrc:~$ modprobe -l | grep 1712
kernel/sound/pci/ice1712/snd-ice1712.ko
kernel/sound/pci/ice1712/snd-ice17xx-ak4xxx.ko
kernel/sound/pci/ice1712/snd-ice1724.ko

I'll blacklist snd-ice1712. I also don't need firewire, wifi and
bluetooth. I don't know the modules names, but I'll find out their
names and unload or blacklist them.

Perhaps the mouse is the culprit. When I didn't own the RME,
but only the TerraTec's, they 1. didn't share their IRQs and 2. I used
a PS/2 mouse, so another USB slot, with another IRQ might improve
something.

spinymouse@qrc:~$ cat /proc/interrupts
           CPU0       CPU1       
  0:        132          0   IO-APIC-edge      timer
  1:          3       5862   IO-APIC-edge      i8042
  7:          1          0   IO-APIC-edge      parport0
  8:          0          1   IO-APIC-edge      rtc0
  9:          0          0   IO-APIC-fasteoi   acpi
 14:          0          0   IO-APIC-edge      pata_atiixp
 15:          0          0   IO-APIC-edge      pata_atiixp
 16:          1     221477   IO-APIC-fasteoi   ohci_hcd:usb2
 17:          0          2   IO-APIC-fasteoi   ohci_hcd:usb3,
                                               ohci_hcd:usb5
18:          0    6549804   IO-APIC-fasteoi   ohci_hcd:usb4,
                                   ohci_hcd:usb6, snd_hdspm

spinymouse@qrc:~$ /etc/init.d/rtirq status

  PID CLS RTPRIO  NI PRI %CPU STAT COMMAND      
   62 FF      90   - 130  0.0 S    irq/8-rtc0   
  806 FF      85   - 125  0.2 S    irq/18-snd_hdsp      
  838 FF      85   - 125  0.0 S    irq/20-snd_ice1      
  850 FF      85   - 125  0.0 S    irq/21-snd_ice1      
   54 FF      80   - 120  0.0 S    irq/19-ehci_hcd      
   55 FF      80   - 120  0.0 S    irq/16-ohci_hcd      
   56 FF      79   - 119  0.0 S    irq/17-ohci_hcd      
   58 FF      78   - 118  0.0 S    irq/18-ohci_hcd      
   59 FF      78   - 118  0.0 S    irq/17-ohci_hcd      
   60 FF      77   - 117  0.1 S    irq/18-ohci_hcd      
   61 FF      75   - 115  0.0 S    irq/1-i8042  
   24 FF      50   -  90  0.0 S    irq/9-acpi   
   46 FF      50   -  90  0.0 S    irq/22-ahci  
  232 FF      50   -  90  0.0 S    irq/14-pata_ati      
  233 FF      50   -  90  0.0 S    irq/15-pata_ati      
  274 FF      50   -  90  0.0 S    irq/22-firewire      
  620 FF      50   -  90  0.0 S    irq/7-parport0       
  780 FF      50   -  90  0.0 S    irq/43-radeon        
 1104 FF      50   -  90  0.0 S    irq/42-eth0  
    3 FF       1   -  41  0.1 S    ksoftirqd/0  
   15 FF       1   -  41  0.1 S    ksoftirqd/1
 19:          0          2   IO-APIC-fasteoi   ehci_hcd:usb1
 20:          0          0   IO-APIC-fasteoi   snd_ice1712
 21:          0          0   IO-APIC-fasteoi   snd_ice1712
 22:          5     113762   IO-APIC-fasteoi   ahci, firewire_ohci
 42:      17275         24   PCI-MSI-edge      eth0
 43:         59      19419   PCI-MSI-edge      radeon

Regards,
Ralf

PS: Thank you Len, I'll test if MIDI will work, after removing the envy
driver module and if I don't need the MIDI ports, I anyway could
blacklist the module.

Attachment: quantal-rt
Description: Binary data

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