Changing hw.snd.pcm0.buffersize in 4.10.

Sandy Rutherford sandy at krvarr.bc.ca
Mon Dec 13 20:03:39 PST 2004


>>>>> On Mon, 13 Dec 2004 21:08:02 -0600, 
>>>>> Nikolas Britton <freebsd at nbritton.org> said:

 > I'm not sure if it makes a difference but 8192 is not in "quotes" like I 
 > have in my working example and man device.hints says it should look like 
 > this: hint.driver.unit.keyword="value", 

I added the quotes, but still:

[szamoca:6] cat /boot/loader.conf
# -- sysinstall generated deltas -- #
userconfig_script_load="YES"
hint.pcm.0.buffersize="8192"

[szamoca:7] sysctl -a | grep snd
hw.snd.targetirqrate: 32
hw.snd.report_soft_formats: 1
hw.snd.verbose: 1
hw.snd.maxautovchans: 0
hw.snd.pcm0.buffersize: 4096
hw.snd.pcm0.vchans: 4

[szamoca:8] cat /dev/sndstat
FreeBSD Audio Driver (newpcm)
Installed devices:
pcm0: <SB16 DSP 4.02> at io 0x220 irq 5 drq 1:0 bufsz 4096d (1p/1r/4v channels duplex)

So no change.  Also, in 4.10:

[szamoca:9] man device.hints
No manual entry for device.hints

So perhaps device.hints is not supported in 4.10.

 > also, have you tried playing 
 > with targetirqrate? 

Yes, quite a bit.  I set hw.snd.verbose to 2 and compiled stats for
hw.snd.targetirqrate set to 16, 24, 32, 48, and 64.  There was no
effect to either the perceived sound quality or the rate of underruns
reported by sndstat.

BTW, if it makes any difference, this is an SMP machine --- albeit an
older one.  It has 2 x PII 300MHZ.

Thanks,
Sandy


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