[pulseaudio-discuss] pulseaudio (V5) incorrect rate detection on usb sound card with raspberry

[Tanu Kaskinen]

On Sun, 2014-11-02 at 18:52 +0500, Alexander E. Patrakov wrote:
> 02.11.2014 18:11, Tanu Kaskinen wrote:
> > On Tue, 2014-10-28 at 11:39 +0000, mailing lists wrote:
> >> Hello Tanu,
> >>
> >>> I'm not sure if you mentioned this already before (sorry for not
> >>> bothering to check), but is the PA version the same between the
> >>> machines? If not, then something may have been fixed in PA, but in any
> >>> case it seems more likely to me that there was some change in the kernel
> >>> driver or alsa-lib that fixed the issue that makes PulseAudio conclude
> >>> that the sound card doesn't support 44100 Hz.
> >>
> >> raspbian comes with PA 2, but I did compiled PA 5, just to discard
> >> this type of problems, you can see the output here and yes both test
> >> are with PA 5:
> >>
> >> http://lists.freedesktop.org/archives/pulseaudio-discuss/2014-October/022015.html
> >>
> >> I don't think there is a kernel driver or alsa-lib bug because other
> >> software like the Music Player Daemon haven't problem using the alsa
> >> device with only 10% of cpu usage (mp3 decoding), but with mpd
> >> Pulseaudio output or any other program (local or remote) cpu is
> >> 100% ... you known music is 44100 and PA detects a 48000 sound card so
> >> it needs resampling.
> >>
> >> That I don't understand is how PA determines sound card capabilities....
> >>
> >> any clue?
> >
> > If the same PulseAudio version works on a newer kernel but not on an
> > older kernel, then that very strongly suggests that something was
> > changed in the kernel that made it work. If MPD works also on the older
> > kernel, then apparently PulseAudio and MPD do something differently.
> > Feel free to compare the source code of MPD and PulseAudio to see if
> > PulseAudio does something wrong (I lack the motivation to do that
> > myself). The "Device %s doesn't support %u Hz, changed to %u Hz."
> > message is printed from src/modules/alsa/alsa-util.c, so that's a good
> > place to start.
> 
> Tanu, please ignore the "issue". It was caused by a bad edit to 
> /usr/share/alsa/alsa.conf.
> 
> The bad edit was:
> 
> -pcm.front cards.pcm.default
> +##pcm.front cards.pcm.front
> +pcm.front cards.pcm.default
> 
> As a result, the front:0 device was redirected to dmix, which by default 
> accepts only 48 kHz.

Oops, I didn't remember to check if the mail had already got answers
before I replied to it! I was reading the mails in oldest-first order,
without threading... Good that the issue was resolved!

-- 
Tanu