[alsa-devel] soc-dsp programming model for loopbacks
lrg at ti.com
Thu Feb 2 12:17:52 CET 2012
On Wed, 2012-02-01 at 11:50 +0000, Girdwood, Liam wrote:
> On 1 February 2012 09:07, Vinod Koul <vinod.koul at linux.intel.com> wrote:
> > On Wed, 2012-01-25 at 17:07 +0000, Liam Girdwood wrote:
> >> We could eventually remove steps 2 and 4 for the FE DAI link, and look
> >> at hard coding the hw_params() in the mach driver for the loopback
> >> link.
> >> That way the only user space driven actions would be to configure the
> >> mixers in the CODEC and DSP for the correct route. DAPM would then
> >> detect the path and Dynamic PCM would use the hard coded configuration
> >> or bespoke mach driver logic to configure the loopback DAI link based
> >> on
> >> use case. This would have to be done after the basic Dynamic PCM
> >> infrastructure was upstream though (unless you have a patch atm).
> > Hi,
> > Sorry to join the party late :-)
No worries ;-)
> > Liam, if we configure the hw_params in the machine driver statically,
> > represent the DSP using a map along with a codec kind of modeling.
In OMAP we reconfigure (or fixup) some of the hw_params() in the machine
driver for a BE DAI link that cant operate at the requested FE params.
The ABE takes care of any conversion though.
> > Would the BEs be triggered on from soc_dsp_runtime_update() when the
> > loopback is established thru the DSP.
> > This way we avoid all the "virtual" FEs. Use loopback to turn on codec
> > and DSP (thru BEs)
> > Would this make sense, or I need more coffee :)
In the code base atm we have to use a FE pcm to trigger the BE loopback
DAIs. however, the intention is to use Mark's CODEC <-> CODEC DAI link
work to support the loopback with hard coded params in the machine
driver. This would save the need for any FE pcm operations.
> > --
> > ~Vinod
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