Noisy mouse

Polytropon freebsd at
Sat Nov 29 04:21:45 PST 2008

On Sat, 29 Nov 2008 13:43:45 +0200, "Roey Dror" <darwinian.empire at> wrote:
> I'm using FreeBSD 7.0 (i386) with the IceWM window manager. The sound
> seems to work when playing files with xmms.
> When my speakers are turned on, I hear noise whenever I move my mouse
> or make a keystroke. Is this a bug, or a strange feature? How do i
> turn it off?

I have a similar observation here, allthough you can hear the
"noisy mouse" only when the mixer settings vol is 100. In my
opinion, this seems to be a kind of electromagnetic
interference, but I didn't test this theory yet. Or it has to
do with data fransfers during mouse movement / keystrokes?
USB uses polling, but maybe some weird interrupt problem?
Anyone remembers Sound Blaster problems when printing on
a parallel printer (IRQ7)?

My settings are different from yours:

	% uname -r
	7.0-STABLE (ca. Aug 2008)

	% cat /dev/sndstat 
	FreeBSD Audio Driver (newpcm: 32bit 2007061600/i386)
	Installed devices:
	pcm0: <CMedia CMI8738> at io 0xd800 irq 16 [MPSAFE]
		(1p:1v/1r:1v channels duplex default)

	% dmesg | grep pcm
	pcm0: <CMedia CMI8738> port 0xd800-0xd8ff irq 16 at device 7.0 on pci3
	pcm0: [ITHREAD]

	% sysctl -a | grep snd
	hw.snd.latency_profile: 1
	hw.snd.latency: 5
	hw.snd.report_soft_formats: 1
	hw.snd.compat_linux_mmap: 0
	hw.snd.feeder_buffersize: 16384
	hw.snd.feeder_rate_round: 25
	hw.snd.feeder_rate_max: 2016000
	hw.snd.feeder_rate_min: 1
	hw.snd.verbose: 1
	hw.snd.maxautovchans: 16
	hw.snd.default_unit: 0
	hw.snd.version: 2007061600/i386
	hw.snd.default_auto: 0

As you described, moving the mouse and pressing keys on the
keyboard result in strange "sound effects". I have a Sun USB
type 6 keyboard + type 6 mouse.

I'm using a separate sound card (PCI) because I diskike the
"AC'97" CPU sound card emulation. :-)

>From Magdeburg, Germany
Happy FreeBSD user since 4.0
Andra moi ennepe, Mousa, ...

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