[PATCH] thinkpad-acpi: fix return value of volume callbacks

[Clemens Ladisch <clemens@ladisch.de>]

Fix up the volume status setting functions to return a non-zero value if
the control value has changed, so that the ALSA framework can correctly
generate control change notifications.

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

--- linux/drivers/platform/x86/thinkpad_acpi.c
+++ linux/drivers/platform/x86/thinkpad_acpi.c
@@ -6537,8 +6537,11 @@ static int volume_set_mute_ec(const bool
 	n = (mute) ? s | TP_EC_AUDIO_MUTESW_MSK :
 		     s & ~TP_EC_AUDIO_MUTESW_MSK;
 
-	if (n != s)
+	if (n != s) {
 		rc = volume_set_status_ec(n);
+		if (!rc)
+			rc = 1;
+	}
 
 unlock:
 	mutex_unlock(&volume_mutex);
@@ -6569,8 +6572,11 @@ static int volume_set_volume_ec(const u8
 
 	n = (s & ~TP_EC_AUDIO_LVL_MSK) | vol;
 
-	if (n != s)
+	if (n != s) {
 		rc = volume_set_status_ec(n);
+		if (!rc)
+			rc = 1;
+	}
 
 unlock:
 	mutex_unlock(&volume_mutex);