Hi! Recently I bought an external USB sound card (Music Fidelity V-DAC). If I plug in the USB cable the sound device is recognized by Phonon in KDE4 (kdemod).
If I play an audio file in Amarok (or VLC) the audio is indeed redirected to the USB sound card and played correctly. However, if I use my USB mouse, or USB keyboard dropouts are occurring in the audio signal. It seems that other USB devices are interfering with my USB sound card.
Arch Linux with kernel 2.6.33 and kdemod 4. Phonon backend is Xine. I also tried gstreamer, but this crashes Amarok/
$ cat /proc/asound/cards 0 [Intel ]: HDA-Intel - HDA Intel HDA Intel at 0xfebfc000 irq 29 1 [default ]: USB-Audio - USB Audio DAC Burr-Brown from TI USB Audio DAC at usb-0000:00:1d.1-1, full s
$ dmesg | grep Audio input: Burr-Brown from TI USB Audio DAC as /devices/pci0000:00/0000:00:1d.1/usb3/3-1/3-1:1.2/input/input12 generic-usb 0003:08BB:2706.0003: input,hidraw2: USB HID v1.00 Device [Burr-Brown from TI USB Audio DAC ] on usb-0000:00:1d.1-1/input2 input: Burr-Brown from TI USB Audio DAC as /devices/pci0000:00/0000:00:1d.1/usb3/3-1/3-1:1.2/input/input15 generic-usb 0003:08BB:2706.0005: input,hidraw2: USB HID v1.00 Device [Burr-Brown from TI USB Audio DAC ] on usb-0000:00:1d.1-1/input2
I also tried an Ubuntu (9.10) live CD. Using ALSA or Pulseaudio a clean audio signal without dropouts is produced.
I wonder if someone can help me with this problem, or point me to more information. Thanks!
Last edited by boomerang (2010-04-25 17:47:15)
In /etc/modprobe.d/blah.conf I have:
options snd-hda-intel model=acer-aspire-8930g enable_msi=1 index=0
That "enable_msi=1" is important, so that "cat /proc/interrupts" shows hda_intel on its *own* interrupt. Hopefully that will stop the dropouts.
Last edited by brebs (2010-04-19 08:34:30)
Thanks for your suggestion. I added the following line to my /etc/modprobe.d/modprobe.conf file:
options snd-usb-audio enable_msi=1
After a reboot the problem still persists. I also tried another suggestion from this forum:
options snd-usb-audio nrpacks=1
This doesn't work either. I tried to change settings in /etc/security/limits.conf, which looks like this:
@audio - rtprio 99 @audio - nice -10 @audio - memlock 250000
The USB sound card doesn't share a IRQ with another USB devices, as can be seen here:
$cat /proc/interrupts CPU0 CPU1 0: 124157 0 IO-APIC-edge timer 1: 2102 0 IO-APIC-edge i8042 8: 182 0 IO-APIC-edge rtc0 9: 523 0 IO-APIC-fasteoi acpi 12: 3780 0 IO-APIC-edge i8042 14: 15944 0 IO-APIC-edge ata_piix 15: 5177 0 IO-APIC-edge ata_piix 16: 29001 0 IO-APIC-fasteoi uhci_hcd:usb5, firewire_ohci, nvidia 17: 0 0 IO-APIC-fasteoi mmc0 18: 0 0 IO-APIC-fasteoi uhci_hcd:usb4 19: 44788 0 IO-APIC-fasteoi uhci_hcd:usb3 23: 387 0 IO-APIC-fasteoi ehci_hcd:usb1, uhci_hcd:usb2 28: 1608 0 PCI-MSI-edge eth0 29: 932 0 PCI-MSI-edge hda_intel 30: 0 0 PCI-MSI-edge iwl3945 NMI: 0 0 Non-maskable interrupts LOC: 22401 65060 Local timer interrupts SPU: 0 0 Spurious interrupts PMI: 0 0 Performance monitoring interrupts PND: 0 0 Performance pending work RES: 89856 104215 Rescheduling interrupts CAL: 1409 563 Function call interrupts TLB: 1733 2536 TLB shootdowns TRM: 0 0 Thermal event interrupts THR: 0 0 Threshold APIC interrupts MCE: 0 0 Machine check exceptions MCP: 2 2 Machine check polls ERR: 0 MIS: 0
$ lsusb Bus 003 Device 002: ID 046d:c03d Logitech, Inc. M-BT96a Pilot Optical Mouse [b]Bus 003 Device 003: ID 08bb:2706 Texas Instruments Japan [/b] Bus 003 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 001 Device 002: ID 07ab:fc88 Freecom Technologies Bus 001 Device 006: ID 05e1:0501 Syntek Semiconductor Co., Ltd DC-1125 Webcam Bus 001 Device 001: ID 1d6b:0002 Linux Foundation 2.0 root hub Bus 004 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 005 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub Bus 002 Device 002: ID 046d:c317 Logitech, Inc. Wave Corded Keyboard Bus 002 Device 001: ID 1d6b:0001 Linux Foundation 1.1 root hub
Any other suggestions?
I even tried to disable the internal sound card by blacklisting it:
.. but still no success
Last edited by boomerang (2010-04-19 20:04:33)
I saw a possibly related bug here. Kernel26-lts is compiled with the option CONFIG_USB_EHCI_TT_NEWSCHED enabled:
$ zcat /proc/config.gz | grep CONFIG_USB_EHCI_TT CONFIG_USB_EHCI_TT_NEWSCHED=y
I tried this kernel, but the problem still persists.. Could this be another kernel issue? No matter what player or audio server (Pulseaudio, ALSA, JACK) I use, this problem occurs.
Last edited by boomerang (2010-04-20 21:23:34)
Perhaps you need to try a powered hub on the USB port for audio?
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I will mark this thread as SOLVED.
I just found out that the nvidia driver was the cause of the audio dropouts. I'm now using the nouveau driver instead (using the installation instructions in the Arch wiki), and the problem is solved. Thanks for the other suggestions!