[PATCH] ucm: Document PlaybackPCMIsDummy and CapturePCMIsDummy values

[Tanu Kaskinen <tanu.kaskinen@linux.intel.com>]

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>
---
 include/use-case.h | 10 ++++++++++
 1 file changed, 10 insertions(+)

diff --git a/include/use-case.h b/include/use-case.h
index 4e13249..f30168f 100644
--- 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
-- 
1.9.3