[LAU] Realtime Privilege, WAS:Re: OT: what is happening with RT kernel development?

On Fri, 29 Mar 2013 23:24:09 +0100, <jonetsu@email-addr-hidden> wrote:
> Actually, jackd (qjackctl) does not see the 1010LT card.
>
> lspci shows:
>
> 05:01.0 Multimedia audio controller: VIA Technologies
> Inc. ICE1712 [Envy24] PCI Multi-Channel I/O Controller (rev 02)
>
> Although qjackctl's message shows:
>
> Fri Mar 29 18:12:41 2013: control device hw:0
>

I'm fairly sure your m-audio card is at hw:1 in this case. There's no
guarantee in which order the cards end up at each boot.
To make sure you always start your m-audio card, I usually always use the
name. Instead of hw:0 I would use hw:M66. You can get the name from
checking the file /proc/asound/cards as I do below

$ cat /proc/asound/cards
  0 [SB ]: HDA-Intel - HDA ATI SB
                       HDA ATI SB at 0xfe300000 irq 16
  1 [M66 ]: ICE1712 - M Audio Delta 66
                       M Audio Delta 66 at 0xd040, irq 21
  2 [NVidia ]: HDA-Intel - HDA NVidia
                       HDA NVidia at 0xfe080000 irq 24

> Fri Mar 29 18:12:41 2013: Acquired audio card Audio0
>
> Fri Mar 29 18:12:41 2013: creating alsa driver
> ... hw:0|hw:0|1024|2|44100|0|0|nomon|swmeter|-|32bit
>
> Fri Mar 29 18:12:41 2013: ALSA: final selected sample format for
> capture: 32bit integer little-endian
>
> Fri Mar 29 18:12:41 2013: ALSA: use 2 periods for capture
>
> Fri Mar 29 18:12:41 2013: ALSA: final selected sample format for
> playback: 32bit integer little-endian
>
> Fri Mar 29 18:12:41 2013: ALSA: use 2 periods for playback
>
> Fri Mar 29 18:12:41 2013: ERROR: Cannot use real-time
> scheduling (RR/10)(1: Operation not permitted)

This means you don't have realtime privilege. You need to do two things.

First, make sure you have a file called /etc/security/limits.d/audio.conf
with the contents (if you didn't enable realtime privilege during install,
the file will be named /etc/security/limits.d/audio.conf,disabled):

# Provided by the jackd package.
#
# Changes to this file will be preserved.
#
# If you want to enable/disable realtime permissions, run
#
# dpkg-reconfigure -p high jackd

@audio - rtprio 95
@audio - memlock unlimited
#@audio - nice -19

Second, add yourself to audio group. You can do this with the command:
sudo usermod -a -G audio $USER
Then, reboot for changes to take effect.

>
> Fri Mar 29 18:12:41 2013: ERROR: AcquireSelfRealTime
> error
>
> Cannot lock down 82274202 byte memory area (Cannot allocate
> memory)
>
> And qjackctl ony has two capture inputs, instead of the ones from
> the 1010LT card. The two errors in there made me look at a low
> latency kernel. Now, I'm not sure if it would solve the problem.
>
>

So, these errors have nothing to do with the kernel. A realtime kernel
does not provide realtime privilege.

You accidentally sent this mail directly to me ;)
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Received on Sat Mar 30 00:15:06 2013