[alsa-devel] [bug] Missing "front" definition for byt-max98090

[Takashi Iwai]

On Thu, 07 Sep 2017 14:25:44 +0200,
Tanu Kaskinen wrote:
> 
> PulseAudio 11 stopped using "hw:" as a fallback for analog stereo if
> "front:" doesn't work. This caused a regression on "Toshiba Chromebook
> 2 (Swanky)", because PulseAudio doesn't any more do automatic mixer
> adjustments when plugging in headphones. Apparently on this machine
> "hw:1,0" works fine as a substitute for "front:1,0", but we're not
> going to revert the change in PulseAudio, so could someone add the
> "front" definition for this machine in alsa-lib? Unfortunately I'm not
> proficient enough in the alsa-lib configuration system to make a patch
> myself.

Well, this is about the device that has no alsa-lib config.  So far,
we assumed that 'front' is available only when defined for the card.
But now PA mandates it...  Hmm.  I guess it's no big problem to add a
fallback to hw for the front PCM.

The patch below should work for such a device.  It's a patch to
alsa-lib source, but basically you can modify similarly the file
/usr/share/alsa/pcm/front.conf directly, too.

If it's confirmed to work, I'll merge the patch.

Maybe we can release alsa-lib 1.1.5 along with 4.13 kernel, so a
quicker reply would be appreciated.


thanks,

Takashi

---
diff --git a/src/conf/pcm/front.conf b/src/conf/pcm/front.conf
index 7aff0cbf007d..377aef33daa7 100644
--- a/src/conf/pcm/front.conf
+++ b/src/conf/pcm/front.conf
@@ -46,6 +46,15 @@ pcm.!front {
 				".pcm.front." $DEV ":CARD=" $CARD
 			]
 		}
+		default {
+			# use plughw as default
+			type plug
+			slave.pcm {
+				type hw
+				card $CARD
+			}
+			hint.device 0
+		}
 	}
 	hint {
 		show {