[PATCH v2 1/3] ASoC: dapm: Fix widget lookup with prefixed names across DAPM contexts

[Chancel Liu]

Currently dapm_find_widget() manually constructs a prefixed widget name
based on the provided DAPM context and compares it using strcmp(). This
happens to work in most cases because callers usually know which DAPM
context the target widget belongs to and pass in the matching DAPM
context.

However, this assumption breaks when search_other_contexts is enabled.
In such cases, callers may intentionally pass a different DAPM context,
while searching for a widget that actually belongs to another DAPM
context.

For example, when searching for a "DAC" widget, the widget belongs to
the codec DAPM and be registered with a codec prefix, while the caller
passes card->dapm and intends to search across all DAPM contexts. The
current implementation incorrectly applies the caller card DAPM causing
the lookup to fail even though the widget exists on the card.

Use snd_soc_dapm_widget_name_cmp() instead, which compares widget names
using the widget's own DAPM context and prefix. It fixes widget lookup
failures when searching across different DAPM contexts on the card.

Fixes: ae4fc532244b ("ASoC: dapm: use component prefix when checking widget names")
Signed-off-by: Chancel Liu <chancel.liu@xxxxxxx>
Assisted-by: Cody:Claude-3.5-Sonnet
---
 sound/soc/soc-dapm.c | 13 +------------
 1 file changed, 1 insertion(+), 12 deletions(-)

diff --git a/sound/soc/soc-dapm.c b/sound/soc/soc-dapm.c
index d6192204e613..c5b80d9ed64b 100644
--- a/sound/soc/soc-dapm.c
+++ b/sound/soc/soc-dapm.c
@@ -2906,20 +2906,9 @@ static struct snd_soc_dapm_widget *dapm_find_widget(
 {
 	struct snd_soc_dapm_widget *w;
 	struct snd_soc_dapm_widget *fallback = NULL;
-	char prefixed_pin[80];
-	const char *pin_name;
-	const char *prefix = dapm_prefix(dapm);
-
-	if (prefix) {
-		snprintf(prefixed_pin, sizeof(prefixed_pin), "%s %s",
-			 prefix, pin);
-		pin_name = prefixed_pin;
-	} else {
-		pin_name = pin;
-	}
 
 	for_each_card_widgets(dapm->card, w) {
-		if (!strcmp(w->name, pin_name)) {
+		if (!snd_soc_dapm_widget_name_cmp(w, pin)) {
 			if (w->dapm == dapm)
 				return w;
 			else
-- 
2.50.1