ALSA: usb-audio: Handle error for the current selector gracefully

Currently we bail out when the device returns an error or an invalid
value for the current clock selector value via
uac_clock_selector_get_val().  But it's possible that the device is
really uninitialized and waits for the setup of the proper route at
first.

For handling such a case, this patch lets the driver dealing with the
error or the invalid error more gracefully, choosing the clock source
automatically instead.

Link: https://lore.kernel.org/r/20210518152112.8016-3-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

diff --git a/sound/usb/clock.c b/sound/usb/clock.c
index 48a79f1..772478c 100644 (file)
--- a/sound/usb/clock.c
+++ b/sound/usb/clock.c
@@ -299,8 +299,11 @@ static int __uac_clock_find_source(struct snd_usb_audio *chip,
                /* the entity ID we are looking for is a selector.
                 * find out what it currently selects */
                ret = uac_clock_selector_get_val(chip, clock_id);
-               if (ret < 0)
-                       return ret;
+               if (ret < 0) {
+                       if (!chip->autoclock)
+                               return ret;
+                       goto find_others;
+               }
 
                /* Selector values are one-based */
 
@@ -309,7 +312,10 @@ static int __uac_clock_find_source(struct snd_usb_audio *chip,
                                "%s(): selector reported illegal value, id %d, ret %d\n",
                                __func__, clock_id, ret);
 
-                       return -EINVAL;
+                       if (!chip->autoclock)
+                               return -EINVAL;
+                       ret = 0;
+                       goto find_others;
                }
 
        find_source:
@@ -326,6 +332,7 @@ static int __uac_clock_find_source(struct snd_usb_audio *chip,
                if (!validate || ret > 0 || !chip->autoclock)
                        return ret;
 
+       find_others:
                /* The current clock source is invalid, try others. */
                for (i = 1; i <= pins; i++) {
                        if (i == cur)