[alsa-devel] [Alsa-devel] [RFC][RFT] Adding support for Jazz16 based sound cards

Rask Ingemann Lambertsen rask at sygehus.dk
Tue Mar 27 00:07:16 CEST 2007

On Mon, Mar 12, 2007 at 12:28:00PM +0100, Takashi Iwai wrote:
> At Mon, 12 Mar 2007 00:24:36 +0100,
> Rask Ingemann Lambertsen wrote:
> >    I tried to include u-law support, but it doesn't sound right and playback
> > speed is about one third of what it should be. I could really use some
> > documentation here. I'll remove it before submitting a final patch if I
> > don't get it to work.
> OK.

   I never got u-law or a-law to work. I tried various ADPCM formats which
gave correct playback speed, but much noise. There seems to be a Media
Vision ADPCM format, which is probably what the Jazz16 wants, but I have no
information about that format. FWIW, the playback_format/capture_format
values I've tried are:

#define SB_DSP_ALAW_OUTPUT_AUTO         0x1F
#define SB_DSP_ALAW_INPUT_AUTO          0x2F
#define SB_DSP_ULAW_OUTPUT_AUTO         0x7f
#define SB_DSP_ULAW_INPUT_AUTO          0x8f
#define SB_DSP_ADPCM_OUTPUT_AUTO        0x7C+1
#define SB_DSP_ADPCM_INPUT_AUTO         0x8C+1

> >    Setting the irq of the MPU-401 port requires the SB part to be active and
> > even worse, DSP commands need to be sent. Would it be better to just use the
> > MPU-401 port without an irq and avoid the complexity?
> Isn't SB part already active?  It's fine with non-irq version (which
> uses timer) if the code gets too complicated, of course.

   It turned out that I can't disable just the MPU port.

Rask Ingemann Lambertsen

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