Choppy sound with nForce4 chipset during network activity

Jos Backus jos at
Thu Jul 12 16:44:03 UTC 2007

Hi. I am noticing choppy sound playback during network activity.  Could this
be related to the IRQ sharing between pcm0 and nfe0?

lizzy:~% uname -a
FreeBSD lizzy.catnook.local 7.0-CURRENT FreeBSD 7.0-CURRENT #6: Sun Jul  8
14:41:29 PDT 2007     root at lizzy.catnook.local:/usr/obj/usr/src/sys/LIZZY
lizzy:~% cat /dev/sndstat 
FreeBSD Audio Driver (newpcm: 32bit 2007061600/i386)
Installed devices:
pcm0: <nVidia nForce4> at io 0xdc00, 0xe000 irq 23 bufsz 32768 kld snd_ich
[MPSAFE] (1p:3v/1r:1v channels duplex default)
lizzy:~% vmstat -i
interrupt                          total       rate
irq1: atkbd0                        9201          0
irq4: uart0                          129          0
irq6: fdc0                             1          0
irq12: psm0                       394582          3
irq22: atapci2                   2064956         16
irq23: pcm0 nfe0                 3970028         32
cpu0: timer                    244997857       1999
Total                          251436754       2052

Jos Backus
jos at

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