[alsa-devel] Backported sbxfi driver, possible fix

Takashi Iwai tiwai at suse.de
Mon Oct 27 07:28:51 CET 2008

At Mon, 27 Oct 2008 08:32:05 +0300,
The Source wrote:
> Alexander E. Patrakov пишет:
> > Takashi Iwai wrote:
> >   
> >> A few important features are in my mind:
> >> - continuous rate support
> >>     
> >
> > In the sources, you have:
> >
> >   
> >> Note: 44.1kHz is possible, but is more complex because it uses a method
> >> whereby the channel ring marks each sample in the channel ring as valid
> >> or not, so to get 44.1kHz, some samples are simply tagged invalid. The
> >> "channel ring" is not the ring buffer that is used to get sound samples
> >> to the card. The "channel ring" is used to pass samples between
> >> different processing modules on the card. One of these processing
> >> modules is the SRC, another is the INs/OUTs, another is the hardware
> >> mixer, and yet another is the DSP.
> >>     
> >
> > Do I understand correctly that the card internally resamples the sound 
> > to a different rate using the zero-order-hold method? If so, I'd rather 
> > not see this feature at all unless the "i_want_horrible_sound" parameter 
> > is passed, because software can do it better, and some program will 
> > surely default to using this hardware misfeature.
> >
> > OTOH, Wine is doing this for ages and nobody except me complains 
> > (http://bugs.winehq.org/show_bug.cgi?id=14717)
> >
> >   
> Wine causes sound corruption with this driver for me (along with some 
> other software like Pulseaudio).

Does it happen also with base_rate=48000 option?

It'd be helpful if someone can summarize the working and non-working
cases.  For example,

global info:
1. sbxfi driver version (date & HEADs)
2. base_rate value
3. system details (x86-64, distro, kernel version, etc)

for each app:
A. Application name / version
B. working or not-working, problem descriptions
C. ALSA or OSS (you can see it in /proc/asound/card*/pcm0/sub0/hw_params)
D. period_size and buffer_size (ditto, or in kernel message)
E. any special options

Maybe also nice on Wiki...



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