[RFC PATCH] ASoC: dapm: Invalidate only paths reachable for a given stream

[Szymon Mielczarek <szymonx.mielczarek@linux.intel.com>]

By resetting the cached number of endpoints for all card's widgets we may
overwrite previously cached values for other streams. The situation may
happen especially when running streams simultaneously.

Signed-off-by: Szymon Mielczarek <szymonx.mielczarek@linux.intel.com>
---
 sound/soc/soc-dapm.c | 50 ++++++++++++++++++++++++++++++++------------
 1 file changed, 37 insertions(+), 13 deletions(-)

diff --git a/sound/soc/soc-dapm.c b/sound/soc/soc-dapm.c
index d09bdca63c62..10819b3e0b98 100644
--- a/sound/soc/soc-dapm.c
+++ b/sound/soc/soc-dapm.c
@@ -1128,6 +1128,34 @@ static int dapm_widget_list_create(struct snd_soc_dapm_widget_list **list,
 	return 0;
 }
 
+/*
+ * Recursively reset the cached number of inputs or outputs for the specified
+ * widget and all widgets that can be reached via incoming or outcoming paths
+ * from the widget.
+ */
+static void invalidate_paths_ep(struct snd_soc_dapm_widget *widget,
+	enum snd_soc_dapm_direction dir)
+{
+	enum snd_soc_dapm_direction rdir = SND_SOC_DAPM_DIR_REVERSE(dir);
+	struct snd_soc_dapm_path *path;
+
+	widget->endpoints[dir] = -1;
+
+	snd_soc_dapm_widget_for_each_path(widget, rdir, path) {
+		if (path->weak || path->is_supply)
+			continue;
+
+		if (path->walking)
+			return;
+
+		if (path->connect) {
+			path->walking = 1;
+			invalidate_paths_ep(path->node[dir], dir);
+			path->walking = 0;
+		}
+	}
+}
+
 /*
  * Common implementation for is_connected_output_ep() and
  * is_connected_input_ep(). The function is inlined since the combined size of
@@ -1257,21 +1285,17 @@ int snd_soc_dapm_dai_get_connected_widgets(struct snd_soc_dai *dai, int stream,
 
 	mutex_lock_nested(&card->dapm_mutex, SND_SOC_DAPM_CLASS_RUNTIME);
 
-	/*
-	 * For is_connected_{output,input}_ep fully discover the graph we need
-	 * to reset the cached number of inputs and outputs.
-	 */
-	list_for_each_entry(w, &card->widgets, list) {
-		w->endpoints[SND_SOC_DAPM_DIR_IN] = -1;
-		w->endpoints[SND_SOC_DAPM_DIR_OUT] = -1;
-	}
-
-	if (stream == SNDRV_PCM_STREAM_PLAYBACK)
-		paths = is_connected_output_ep(dai->playback_widget, &widgets,
+	if (stream == SNDRV_PCM_STREAM_PLAYBACK) {
+		w = dai->playback_widget;
+		invalidate_paths_ep(w, SND_SOC_DAPM_DIR_OUT);
+		paths = is_connected_output_ep(w, &widgets,
 				custom_stop_condition);
-	else
-		paths = is_connected_input_ep(dai->capture_widget, &widgets,
+	} else {
+		w = dai->capture_widget;
+		invalidate_paths_ep(w, SND_SOC_DAPM_DIR_IN);
+		paths = is_connected_input_ep(w, &widgets,
 				custom_stop_condition);
+	}
 
 	/* Drop starting point */
 	list_del(widgets.next);
-- 
2.17.1