[LAD] Usb Audio Driver

Ralf Mardorf ralf.mardorf at alice-dsl.net
Wed Dec 11 17:01:01 UTC 2013


On Wed, 2013-12-11 at 14:31 -0200, Lucas Takejame wrote:
> We are already using a RT-kernel and I guess we already did everything
> we could do on OS changes to achieve a better latency. My doubt is if
> I can change anything on the snd-usb driver to make it specific to our
> sound card, aiming an improve in latency, since our pedalboard
> (http://portalmod.com/en/index.html) has this sound card fixed and we
> won't need a generic driver to the usb connection. I'm gonna send an
> e-mail to the alsa-devel ML, thanks for the advices!


Linux audio user might be a better place to ask first. Since you're
using Arch, ArchAudio mailing list might be a good place too.

Get rid of as much as you can and avoid shared IRQs. If I only need my
RME card, sometimes I even disable the Envy24 MIDI interfaces.

Often I don't use this script, because it doesn't really improve issues
that much on my machine, but you never know and could try as much tuning
as possible.

Perhaps the links are still helpful, I don't know.

[rocketmouse at archlinux ~]$ cat /usr/local/sbin/tuning
#!/bin/bash

# /usr/local/sbin/tuning - Arch Linux
# 2013/Apr/05

### http://www.mythtv.org/wiki/PCI_Latency
### http://wiki.linuxmusicians.com/doku.php?id=system_configuration#pci_bus_latency

### Bluetooth
#service bluetooth stop

### Network
#service network-manager stop
#service networking stop # does cause serious issues
#modprobe -r r8169 # Ethernet NIC driver

### TerraTec EWX 24/96
#modprobe -r snd_ice1712

### Others
modprobe -r firewire-ohci
modprobe -r firewire_core
#service cups stop
modprobe -r ppdev # parallel port
modprobe -r lp    # printer

### Unbinding devices
echo -n "0000:00:13.2" > /sys/bus/pci/drivers/ohci_hcd/unbind
echo -n "0000:00:13.4" > /sys/bus/pci/drivers/ohci_hcd/unbind

### Log file
l="/var/log/tuning.log"
#echo "$ lspci -v                       "  > $l
#lspci -v                                 >> $l
#echo                                     >> $l
echo "# service rtirq status           "  > $l
service rtirq status                     >> $l
echo "# grep 18: /proc/interrupts"       >> $l
grep 18: /proc/interrupts                >> $l
echo                                     >> $l
echo -n $(date)" - "$(uname -r)" - "     >> $l
cat /etc/issue                           >> $l
echo -e "\n########################################################################\n" ; cat $l

exit 0




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