[maemo-developers] ALSA sound driver for Nokia 770 and DSP programming

[From: Siarhei Siamashka]

On Friday 26 September 2008, Felipe Contreras wrote:
> On Fri, Sep 26, 2008 at 12:06 AM, Siarhei Siamashka
>
> <siarhei.siamashka at gmail.com> wrote:
> > On Thursday 25 September 2008, Felipe Contreras wrote:
> >> On Thu, Sep 25, 2008 at 10:07 PM, Siarhei Siamashka
> >
> > [...]
> >
> >> > Now regarding why we may want it. Once if we get a good, low latency,
> >> > fully functional and reliable ALSA sound driver running on ARM, it
> >> > gives maemo community a nice possibility to scrap all the proprietary
> >> > DSP binaries. This provides us with a new and shiny 252MHz C55x DSP
> >> > core ready to be used by something else :)
> >> >
> >> > Free linux DSP toolchain from TI [4] supports generation of both DSP
> >> > kernel and DSP tasks for OMAP1 based devices which is sufficient for
> >> > DSP development. The toolchain license was supposed to permit open
> >> > source development (with noncommercial restriction), though the
> >> > license text itself is a bit questionable [5].
> >> >
> >> > With DSP avalable for use and having no need to spend efforts on
> >> > ensuring compatibility and peaceful coexistence with proprietary
> >> > binary codecs (free and proprietary code does not mix well), it should
> >> > be possible to turn Nokia 770 into quite a powerful media player.
> >>
> >> Great stuff!
> >>
> >> Do you plan to use the dsp-gateway or dsp-bridge?
> >
> > Now as you mentioned that, it indeed makes sense to consider other
> > alternatives if they exist. Do you have any links to the information
> > about dspgateway vs. dspbridge comparison
> > (features/performance/reliability)?
> >
> > Using dspgateway has a clear advantage that it is already included in the
> > kernel. And dspgateway is more or less ok, though patching it a bit in
> > order to improve performance will be required.
>
> Not really, but I've been thinking that a comparison would be useful.
> Perhaps some dummy DSP nodes and clients to test them on both would
> help. I have one for the dsp-bridge, but not dsp-gateway.

The first thing that I did when experimenting with dspgateway was
implementation of some simple low level benchmarks to measure communication
time between ARM and DSP and data transfer performance. The results were
quite interesting. I think that now I know dspgateway problems, its
bottlenecks and have some ideas about how to fix them. But that's a 
topic of another long post and I'll try to share this information later.

-- 
Best regards,
Siarhei Siamashka