[alsa-devel] how to mandate the use of PCM plugin?

Raymond Yau superquad.vortex2 at gmail.com
Sat Oct 2 04:11:10 CEST 2010

2010/9/29 David Henningsson <david.henningsson at canonical.com>

> On 2010-09-28 06:07, Raymond Yau wrote:
> > 2010/9/28 Colin Guthrie<gmane at colin.guthr.ie>
> >
> >>
> >>
> >> And today, one of the Canonical guys published his version of a tool to
> >> help here:
> >> http://thread.gmane.org/gmane.comp.audio.pulseaudio.general/7542
> >>
> >> Hope this helps.
> >>
> >> Col
> >>
> >>
> >>
> > why did runtest.sh use a format  FLOAT64_LE which was not supported by PA
> ?
> runtest.sh isn't meant to be used directly in that way, you're supposed
> to run "alsamixertest". Try "alsamixertest -r" and "alsamixertest -h" to
> get started. (Perhaps I should rename the .sh file to something else.)
> That said, if you find a good use case where you want to use it directly
> and need a different sample format - patches welcome (as long as they
> don't break something else).
I just try to see whether this tool can help me to calibrate the 10 band
gain/atten controls of the hardware equalizer of au8830.

Have anyone test your tool on the sound card with ac97 codec ?

It seem that the program keep complain about those controls without dB scale
(e.g. AC97 3D Control - depth and rear depth , .) with the emulated intel8x0
driver  and no volume control with the emulated sb16 in virtualbox

Your program seem really behave as same as pulseaudio server , set the dB
value of control but don't verify the dB value can be set by re-reading the
value since dB -> volume conversion

Even though your program start at 0dB  , ac97 volume controls are in 1.5dB
per step but your program use 2 dB step

Still finding why the program running into infinite loop and try to set dB
to -7xx dB , however amixer does output the min dB when 0%

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