ALSA: usb-audio: Disable USB autosuspend properly in setup_disable_autosuspend()

Rear audio on Lenovo ThinkStation P620 stops working after commit
1965c436 ("ALSA: usb-audio: Disable autosuspend for Lenovo
ThinkStation P620"):
[    6.013526] usbcore: registered new interface driver snd-usb-audio
[    6.023064] usb 3-6: cannot get ctl value: req = 0x81, wValue = 0x100, wIndex = 0x0, type = 1
[    6.023083] usb 3-6: cannot get ctl value: req = 0x81, wValue = 0x202, wIndex = 0x0, type = 4
[    6.023090] usb 3-6: cannot get ctl value: req = 0x81, wValue = 0x100, wIndex = 0x0, type = 1
[    6.023098] usb 3-6: cannot get ctl value: req = 0x81, wValue = 0x202, wIndex = 0x0, type = 4
[    6.023103] usb 3-6: cannot get ctl value: req = 0x81, wValue = 0x100, wIndex = 0x0, type = 1
[    6.023110] usb 3-6: cannot get ctl value: req = 0x81, wValue = 0x202, wIndex = 0x0, type = 4
[    6.045846] usb 3-6: cannot get ctl value: req = 0x81, wValue = 0x100, wIndex = 0x0, type = 1
[    6.045866] usb 3-6: cannot get ctl value: req = 0x81, wValue = 0x202, wIndex = 0x0, type = 4
[    6.045877] usb 3-6: cannot get ctl value: req = 0x81, wValue = 0x100, wIndex = 0x0, type = 1
[    6.045886] usb 3-6: cannot get ctl value: req = 0x81, wValue = 0x202, wIndex = 0x0, type = 4
[    6.045894] usb 3-6: cannot get ctl value: req = 0x81, wValue = 0x100, wIndex = 0x0, type = 1
[    6.045908] usb 3-6: cannot get ctl value: req = 0x81, wValue = 0x202, wIndex = 0x0, type = 4

I overlooked the issue because when I was working on the said commit,
only the front audio is tested. Apology for that.

Changing supports_autosuspend in driver is too late for disabling
autosuspend, because it was already used by USB probe routine, so it can
break the balance on the following code that depends on
supports_autosuspend.

Fix it by using usb_disable_autosuspend() helper, and balance the
suspend count in disconnect callback.

Fixes: 1965c436 ("ALSA: usb-audio: Disable autosuspend for Lenovo ThinkStation P620")
Signed-off-by: Kai-Heng Feng <kai.heng.feng@canonical.com>
Cc: <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20210304043419.287191-1-kai.heng.feng@canonical.comSigned-off-by: Takashi Iwai <tiwai@suse.de>

sound/usb/card.c

@@ -830,6 +830,8 @@ static int usb_audio_probe(struct usb_interface *intf,
 		snd_media_device_create(chip, intf);
 	}
 
+	chip->quirk_type = quirk->type;
+
 	usb_chip[chip->index] = chip;
 	chip->intf[chip->num_interfaces] = intf;
 	chip->num_interfaces++;
@@ -912,6 +914,9 @@ static void usb_audio_disconnect(struct usb_interface *intf)
 	} else {
 		mutex_unlock(&register_mutex);
 	}
+
+	if (chip->quirk_type & QUIRK_SETUP_DISABLE_AUTOSUSPEND)
+		usb_enable_autosuspend(interface_to_usbdev(intf));
 }
 
 /* lock the shutdown (disconnect) task and autoresume */

sound/usb/quirks.c

@@ -547,7 +547,7 @@ static int setup_disable_autosuspend(struct snd_usb_audio *chip,
 				       struct usb_driver *driver,
 				       const struct snd_usb_audio_quirk *quirk)
 {
-	driver->supports_autosuspend = 0;
+	usb_disable_autosuspend(interface_to_usbdev(iface));
 	return 1;	/* Continue with creating streams and mixer */
 }
 

sound/usb/usbaudio.h

@@ -27,6 +27,7 @@ struct snd_usb_audio {
 	struct snd_card *card;
 	struct usb_interface *intf[MAX_CARD_INTERFACES];
 	u32 usb_id;
+	uint16_t quirk_type;
 	struct mutex mutex;
 	unsigned int system_suspend;
 	atomic_t active;