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Registered: 2016-03-01

Posts: 16

KVM and Windows 10 - Crackling sound

Hi guys and ladies,

i have a annoying problem with my Windows 10 gaming VM. In the first weeks the setups works perfectly (no problems or anything else) but now I have crackling sounds everywhere. And no idea where the problem is located.

I recorded the following flac file as an demonstration. The problem is easy to hear - in my opinion: https://drive.google.com/open?id=0B9Fc2 … 2d5SmFWS2M

This is my kvm configuration via virsh. I used PulseAudio with a locale network server.

<domain type='kvm' xmlns:qemu='http://libvirt.org/schemas/domain/qemu/1.0'>
  <name>Windows-Gaming</name>
  <uuid>407dfd38-272f-4f55-8d95-759207d49074</uuid>
  <memory unit='KiB'>16777216</memory>
  <currentMemory unit='KiB'>16777216</currentMemory>
  <vcpu placement='static'>6</vcpu>
  <os>
    <type arch='x86_64' machine='pc-i440fx-2.7'>hvm</type>
    <loader readonly='yes' type='pflash'>/usr/share/ovmf/x64/ovmf_x64.bin</loader>
    <nvram>/var/lib/libvirt/qemu/nvram/Windows-Gaming_VARS.fd</nvram>
    <bootmenu enable='yes'/>
  </os>
  <features>
    <acpi/>
    <apic/>
    <kvm>
      <hidden state='on'/>
    </kvm>
    <vmport state='off'/>
  </features>
  <cpu mode='host-passthrough'>
    <topology sockets='1' cores='6' threads='1'/>
  </cpu>
  <clock offset='localtime'>
    <timer name='rtc' tickpolicy='catchup'/>
    <timer name='pit' tickpolicy='delay'/>
    <timer name='hpet' present='no'/>
  </clock>
  <on_poweroff>destroy</on_poweroff>
  <on_reboot>restart</on_reboot>
  <on_crash>restart</on_crash>
  <pm>
    <suspend-to-mem enabled='no'/>
    <suspend-to-disk enabled='no'/>
  </pm>
  <devices>
    <emulator>/usr/sbin/qemu-system-x86_64</emulator>
    <disk type='block' device='disk'>
      <driver name='qemu' type='raw'/>
      <source dev='/dev/mapper/vg1-gaming'/>
      <target dev='vda' bus='virtio'/>
      <boot order='1'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x08' function='0x0'/>
    </disk>
    <controller type='usb' index='0' model='ich9-ehci1'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x7'/>
    </controller>
    <controller type='usb' index='0' model='ich9-uhci1'>
      <master startport='0'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x0' multifunction='on'/>
    </controller>
    <controller type='usb' index='0' model='ich9-uhci2'>
      <master startport='2'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x1'/>
    </controller>
    <controller type='usb' index='0' model='ich9-uhci3'>
      <master startport='4'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x04' function='0x2'/>
    </controller>
    <controller type='pci' index='0' model='pci-root'/>
    <controller type='ide' index='0'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x01' function='0x1'/>
    </controller>
    <interface type='network'>
      <mac address='52:54:00:16:7f:2f'/>
      <source network='default'/>
      <model type='virtio'/>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x07' function='0x0'/>
    </interface>
    <input type='mouse' bus='ps2'/>
    <input type='keyboard' bus='ps2'/>
    <hostdev mode='subsystem' type='pci' managed='yes'>
      <source>
        <address domain='0x0000' bus='0x01' slot='0x00' function='0x0'/>
      </source>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x03' function='0x0'/>
    </hostdev>
    <hostdev mode='subsystem' type='pci' managed='yes'>
      <source>
        <address domain='0x0000' bus='0x01' slot='0x00' function='0x1'/>
      </source>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x05' function='0x0'/>
    </hostdev>
    <hostdev mode='subsystem' type='usb' managed='yes'>
      <source>
        <vendor id='0x04d8'/>
        <product id='0x00df'/>
      </source>
      <address type='usb' bus='0' port='5'/>
    </hostdev>
    <hostdev mode='subsystem' type='usb' managed='yes'>
      <source>
        <vendor id='0x04b4'/>
        <product id='0x0101'/>
      </source>
      <address type='usb' bus='0' port='3'/>
    </hostdev>
    <hostdev mode='subsystem' type='usb' managed='yes'>
      <source>
        <vendor id='0x1038'/>
        <product id='0x1361'/>
      </source>
      <address type='usb' bus='0' port='4'/>
    </hostdev>
    <redirdev bus='usb' type='spicevmc'>
      <address type='usb' bus='0' port='1'/>
    </redirdev>
    <redirdev bus='usb' type='spicevmc'>
      <address type='usb' bus='0' port='2'/>
    </redirdev>
    <memballoon model='virtio'>
      <address type='pci' domain='0x0000' bus='0x00' slot='0x06' function='0x0'/>
    </memballoon>
  </devices>
  <qemu:commandline>
    <qemu:arg value='-soundhw'/>
    <qemu:arg value='hda'/>
    <qemu:env name='QEMU_AUDIO_DRV' value='pa'/>
    <qemu:env name='QEMU_PA_SERVER' value='localhost'/>
  </qemu:commandline>
</domain>

I do some research and found many topics to misc sound problems, so I try several things to fix this issue:

- I checked the sample rate from the windows vm and my DAC (fiio e10k), they are the same
- I tried additional qemu arguments (e.g. QEMU_PA_SAMPLES) with no result

Currently I'm extremely helpless, i dont know how to debug this problem.

So I hope anybody here have a good tip for me! I would be very grateful.