ALSA: dice: restrict the driver to playback-only devices

At the moment, this driver supports only playback, while FFADO supports
(only) full-duplex devices.  So, prevent conflicts by not claiming
devices that would be better handled by FFADO.

Signed-off-by: Clemens Ladisch <clemens@ladisch.de>

sound/firewire/Kconfig

@@ -12,14 +12,16 @@ config SND_FIREWIRE_LIB
 	depends on SND_PCM
 
 config SND_DICE
-	tristate "DICE devices (EXPERIMENTAL)"
+	tristate "DICE-based DACs (EXPERIMENTAL)"
 	select SND_HWDEP
 	select SND_PCM
 	select SND_FIREWIRE_LIB
 	help
-	  Say Y here to include support for many FireWire audio interfaces
-	  based on the DICE chip family (DICE-II/Jr/Mini) from TC Applied
-	  Technologies.
+	  Say Y here to include support for many DACs based on the DICE
+	  chip family (DICE-II/Jr/Mini) from TC Applied Technologies.
+
+	  At the moment, this driver supports playback only.  If you
+	  want to use devices that support capturing, use FFADO instead.
 
 	  To compile this driver as a module, choose M here: the module
 	  will be called snd-dice.