[PATCH] ALSA: usb-audio: Avoid unnecessary or invalid connector selection at resume

[Takashi Iwai]

The recent fix for the resume on Lenovo machines seems causing a
regression on others.  It's because the change always triggers the
connector selection no matter which widget node type is.

This patch addresses the regression by setting the resume callback
selectively only for the connector widget.

Fixes: 44609fc01f28 ("ALSA: usb-audio: Check connector value on resume")
Cc: <stable at vger.kernel.org>
BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=213897
Signed-off-by: Takashi Iwai <tiwai at suse.de>
---
 sound/usb/mixer.c | 35 ++++++++++++++++++++---------------
 1 file changed, 20 insertions(+), 15 deletions(-)

diff --git a/sound/usb/mixer.c b/sound/usb/mixer.c
index f4cdaf1ba44a..9b713b4a5ec4 100644
--- a/sound/usb/mixer.c
+++ b/sound/usb/mixer.c
@@ -1816,6 +1816,15 @@ static void get_connector_control_name(struct usb_mixer_interface *mixer,
 		strlcat(name, " - Output Jack", name_size);
 }
 
+/* get connector value to "wake up" the USB audio */
+static int connector_mixer_resume(struct usb_mixer_elem_list *list)
+{
+	struct usb_mixer_elem_info *cval = mixer_elem_list_to_info(list);
+
+	get_connector_value(cval, NULL, NULL);
+	return 0;
+}
+
 /* Build a mixer control for a UAC connector control (jack-detect) */
 static void build_connector_control(struct usb_mixer_interface *mixer,
 				    const struct usbmix_name_map *imap,
@@ -1833,6 +1842,10 @@ static void build_connector_control(struct usb_mixer_interface *mixer,
 	if (!cval)
 		return;
 	snd_usb_mixer_elem_init_std(&cval->head, mixer, term->id);
+
+	/* set up a specific resume callback */
+	cval->head.resume = connector_mixer_resume;
+
 	/*
 	 * UAC2: The first byte from reading the UAC2_TE_CONNECTOR control returns the
 	 * number of channels connected.
@@ -3642,23 +3655,15 @@ static int restore_mixer_value(struct usb_mixer_elem_list *list)
 	return 0;
 }
 
-static int default_mixer_resume(struct usb_mixer_elem_list *list)
-{
-	struct usb_mixer_elem_info *cval = mixer_elem_list_to_info(list);
-
-	/* get connector value to "wake up" the USB audio */
-	if (cval->val_type == USB_MIXER_BOOLEAN && cval->channels == 1)
-		get_connector_value(cval, NULL, NULL);
-
-	return 0;
-}
-
 static int default_mixer_reset_resume(struct usb_mixer_elem_list *list)
 {
-	int err = default_mixer_resume(list);
+	int err;
 
-	if (err < 0)
-		return err;
+	if (list->resume) {
+		err = list->resume(list);
+		if (err < 0)
+			return err;
+	}
 	return restore_mixer_value(list);
 }
 
@@ -3697,7 +3702,7 @@ void snd_usb_mixer_elem_init_std(struct usb_mixer_elem_list *list,
 	list->id = unitid;
 	list->dump = snd_usb_mixer_dump_cval;
 #ifdef CONFIG_PM
-	list->resume = default_mixer_resume;
+	list->resume = NULL;
 	list->reset_resume = default_mixer_reset_resume;
 #endif
 }
-- 
2.26.2