[alsa-devel] [PATCH v2 0/1] *** SUBJECT HERE ***

Peter Ujfalusi peter.ujfalusi at nokia.com
Thu Jul 22 12:57:16 CEST 2010


On Thursday 22 July 2010 12:48:32 ext Mark Brown wrote:
> > I principle I of course agree. But it seems - also discussed with the
> > local ALSA specialist - that using static constraints does not work
> > here. HALF_DUPLEX is not one of the SNDRV_PCM_HW_PARAM_'s... or
> > something like that. As a ALSA non-specialist I'd be willing to this
> > leave as it is...
> Could you please get whoever the expert is to get involved in this
> thread?  If this is not currently possible it should probably be.

I think the whole SNDRV_PCM_INFO_HALF_DUPLEX bit cleaning/setting can be left 
out as such.
My point is, that in wl1273_startup, the driver anyway will refuse the non 
correct stream for FM mode. It is checking, that only playback can be started, 
when the FM is in TX mode, and allows only capture, if the chip has been 
configured to FM RX mode. In BT mode the codec can work in full duplex.

And to the issue:
I'm not really sure about it, but at least I have not seen the constraint API 
used for anything, but for hw_params (access mode, formats, sizes, times)...
As I looked at the ALSA core, I don't really noticed, that we can use the 
constraint API for this.

So let's ask Takashi:
Is it possible to use the constraint API for placing HALF_DUPLEX on a stream 
(modifying bits in the info_flags)?


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