[PATCH 2/2] ASoC: qcom: audioreach: only disconnect the route a mixer control owns

[Marc Herrero via B4 Relay]

From: Marc Herrero <marcht@xxxxxxxxx>

Each AudioReach virtual mixer route control ("<BE> Audio Mixer <FE>")
connects a front-end stream graph to a back-end device graph by storing
the source module in the device graph's audioreach_graph_info. Writing 0
to any of these controls clears that link unconditionally, even when the
device graph is connected to a different front end.

When two front ends can feed the same back end the result therefore
depends on write order. On QCS6490 (Radxa Dragon Q6A):

 - alsactl restore writes 'DISPLAY_PORT_RX_0 Audio Mixer MultiMedia2' = 1
   and then 'DISPLAY_PORT_RX_0 Audio Mixer MultiMedia1' = 0, which leaves
   DisplayPort disconnected although the saved state has it connected;
 - the UCM HDMI enable sequence writes
   'RX_CODEC_DMA_RX_0 Audio Mixer MultiMedia2' = 0, which disconnects
   MultiMedia1 from the headphones. A PCM started on MultiMedia1 after
   that never advances (hw_ptr stays at 0).

Only drop the link when it belongs to the control being cleared, that is
when audioreach_is_vmixer_connected() reports it as connected. Writing 0
to a control that is not the active route becomes a no-op, which matches
what its get() callback already returns.

Fixes: e4977b91cff8 ("ASoC: qdsp6: audioreach: Simplify handing FE and BE graph connections")
Cc: stable@xxxxxxxxxxxxxxx
Signed-off-by: Marc Herrero <marcht@xxxxxxxxx>
---
 sound/soc/qcom/qdsp6/topology.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/sound/soc/qcom/qdsp6/topology.c b/sound/soc/qcom/qdsp6/topology.c
index 612d8f03e6e9..e92408e09bac 100644
--- a/sound/soc/qcom/qdsp6/topology.c
+++ b/sound/soc/qcom/qdsp6/topology.c
@@ -1300,7 +1300,7 @@ static int audioreach_put_audio_mixer(struct snd_kcontrol *kcontrol,
 	if (ucontrol->value.integer.value[0]) {
 		audioreach_connect_sub_graphs(data, scontrol, dapm_scontrol, true);
 		snd_soc_dapm_mixer_update_power(dapm, kcontrol, 1, NULL);
-	} else {
+	} else if (audioreach_is_vmixer_connected(data, scontrol, dapm_scontrol)) {
 		audioreach_connect_sub_graphs(data, scontrol, dapm_scontrol, false);
 		snd_soc_dapm_mixer_update_power(dapm, kcontrol, 0, NULL);
 	}

-- 
2.53.0