On Tue, Apr 16, 2024 at 07:56:13AM +0200, Luca Ceresoli wrote: > diff --git a/Documentation/sound/soc/dapm.rst b/Documentation/sound/soc/dapm.rst > index cab40a6b4c96..3a2fde1d31bf 100644 > --- a/Documentation/sound/soc/dapm.rst > +++ b/Documentation/sound/soc/dapm.rst > @@ -17,9 +17,27 @@ recompiling are required for user space applications to use it. DAPM makes > power switching decisions based upon any audio stream (capture/playback) > activity and audio mixer settings within the device. > > -DAPM spans the whole machine. It covers power control within the entire > -audio subsystem, this includes internal codec power blocks and machine > -level power systems. > +DAPM is based on two basic elements, called widgets and routes: > + > + * a **widget** is every part of the audio hardware that can be enabled by > + software when in use and disabled to save power when not in use > + * a **route** is an interconnection between widgets that exists when sound > + can flow from one widget to the other > + > +All DAPM power switching decisions are made automatically by consulting an > +audio routing graph. This graph is specific to each sound card and spans > +the whole sound card, so some DAPM routes connect two widgets belonging to > +different components (e.g. the LINE OUT pin of a CODEC and the input pin of > +an amplifier). > + > +The graph for the STM32MP1-DK1 sound card is shown in picture: > + > +.. kernel-figure:: dapm-graph.svg > + :alt: Example DAPM graph > + :align: center > + > +DAPM power domains > +================== > > There are 4 power domains within DAPM: > > @@ -48,12 +66,6 @@ Stream domain > Enabled and disabled when stream playback/capture is started and > stopped respectively. e.g. aplay, arecord. > > -All DAPM power switching decisions are made automatically by consulting an audio > -routing graph of the whole machine. This graph is specific to each machine and > -consists of the interconnections between every audio component (including > -internal codec components). All audio components that affect power are called > -widgets hereafter. > - > > DAPM Widgets > ============ > The wording LGTM, thanks! Reviewed-by: Bagas Sanjaya <bagasdotme@xxxxxxxxx> -- An old man doll... just what I always wanted! - Clara
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