[alsa-devel] [PATCH] ASoC: Add weak routes for sidetone style paths

[Liam Girdwood]

On 13/06/11 16:53, Mark Brown wrote:
> Normally DAPM will power up any connected audio path. This is not ideal
> for sidetone paths as with sidetone paths the audio path is not wanted in
> itself, it is only desired if the two paths it provides a sidetone between
> are both active. If the sidetone path causes a power up then it can be
> hard to minimise pops as we first power up either the sidetone or the main
> output path and then power the other, with the second power up potentially
> introducing a DC offset.
> 
> Address this by introducing the concept of a weak path. If a path is marked
> as weak then DAPM will ignore that path when walking the graph, though all
> the relevant controls are still available to the application layer to allow
> these paths to be configured.
> 
> Signed-off-by: Mark Brown <broonie at opensource.wolfsonmicro.com>
> ---
>  include/sound/soc-dapm.h |    2 +
>  sound/soc/soc-dapm.c     |   87 ++++++++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 89 insertions(+), 0 deletions(-)

Acked-by: Liam Girdwood <lrg at ti.com>