ucm: Document PlaybackPCMIsDummy and CapturePCMIsDummy values

At least PulseAudio needs special handling for dummy devices. To allow
that to happen automatically, the UCM configuration should contain the
information about which PCMs are dummy.

Signed-off-by: Tanu Kaskinen <tanu.kaskinen@linux.intel.com>
Acked-by: Liam Girdwood <liam.r.girdwood@linux.intel.com>
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/include/use-case.h b/include/use-case.h
index 4e13249..f30168f 100644 (file)
--- a/include/use-case.h
+++ b/include/use-case.h
@@ -258,7 +258,17 @@ int snd_use_case_get_list(snd_use_case_mgr_t *uc_mgr,
  * Recommended names for values:
  *   TQ                        - Tone Quality
  *   PlaybackPCM       - full PCM playback device name
+ *   PlaybackPCMIsDummy        - Valid values: "yes" and "no". If set to "yes", the
+ *                       PCM named by the PlaybackPCM value is a dummy device,
+ *                       meaning that opening it enables an audio path in the
+ *                       hardware, but writing to the PCM device has no
+ *                       effect.
  *   CapturePCM                - full PCM capture device name
+ *   CapturePCMIsDummy - Valid values: "yes" and "no". If set to "yes", the
+ *                       PCM named by the CapturePCM value is a dummy device,
+ *                       meaning that opening it enables an audio path in the
+ *                       hardware, but reading from the PCM device has no
+ *                       effect.
  *   PlaybackRate      - playback device sample rate
  *   PlaybackChannels  - playback device channel count
  *   PlaybackCTL       - playback control device name