ALSA: usb-audio: Avoid superfluous endpoint setup

After splitting to snd_usb_endpoint_set_params() and *_prepare(), the
skip of each function should be checked with different flags, while we
still use ep->need_setup as the single one.  Introduce
ep->need_prepare for indicating the need of prepare, and also add the
missing check of ep->need_setup at the set_params.

Fixes: 2be79d5 ("ALSA: usb-audio: Split endpoint setups for hw_params and prepare (take#2)")
Link: https://lore.kernel.org/r/20221009104212.18877-5-tiwai@suse.de
Signed-off-by: Takashi Iwai <tiwai@suse.de>

Author: tiwai

sound/usb/card.h

@@ -129,7 +129,8 @@ struct snd_usb_endpoint {
 					   in a stream */
 	bool implicit_fb_sync;		/* syncs with implicit feedback */
 	bool lowlatency_playback;	/* low-latency playback mode */
-	bool need_setup;		/* (re-)need for configure? */
+	bool need_setup;		/* (re-)need for hw_params? */
+	bool need_prepare;		/* (re-)need for prepare? */
 
 	/* for hw constraints */
 	const struct audioformat *cur_audiofmt;

sound/usb/endpoint.c

@@ -824,6 +824,7 @@ snd_usb_endpoint_open(struct snd_usb_audio *chip,
 
 		ep->implicit_fb_sync = fp->implicit_fb;
 		ep->need_setup = true;
+		ep->need_prepare = true;
 
 		usb_audio_dbg(chip, "  channels=%d, rate=%d, format=%s, period_bytes=%d, periods=%d, implicit_fb=%d\n",
 			      ep->cur_channels, ep->cur_rate,
@@ -952,7 +953,7 @@ void snd_usb_endpoint_close(struct snd_usb_audio *chip,
 /* Prepare for suspening EP, called from the main suspend handler */
 void snd_usb_endpoint_suspend(struct snd_usb_endpoint *ep)
 {
-	ep->need_setup = true;
+	ep->need_prepare = true;
 	if (ep->iface_ref)
 		ep->iface_ref->need_setup = true;
 	if (ep->clock_ref)
@@ -1335,9 +1336,12 @@ int snd_usb_endpoint_set_params(struct snd_usb_audio *chip,
 				struct snd_usb_endpoint *ep)
 {
 	const struct audioformat *fmt = ep->cur_audiofmt;
-	int err;
+	int err = 0;
 
 	mutex_lock(&chip->mutex);
+	if (!ep->need_setup)
+		goto unlock;
+
 	/* release old buffers, if any */
 	err = release_urbs(ep, false);
 	if (err < 0)
@@ -1386,8 +1390,11 @@ int snd_usb_endpoint_set_params(struct snd_usb_audio *chip,
 	ep->curframesize = ep->curpacksize / ep->cur_frame_bytes;
 
 	err = update_clock_ref_rate(chip, ep);
-	if (err >= 0)
+	if (err >= 0) {
+		ep->need_setup = false;
 		err = 0;
+	}
+
  unlock:
 	mutex_unlock(&chip->mutex);
 	return err;
@@ -1437,7 +1444,7 @@ int snd_usb_endpoint_prepare(struct snd_usb_audio *chip,
 	mutex_lock(&chip->mutex);
 	if (WARN_ON(!ep->iface_ref))
 		goto unlock;
-	if (!ep->need_setup)
+	if (!ep->need_prepare)
 		goto unlock;
 
 	/* If the interface has been already set up, just set EP parameters */
@@ -1491,7 +1498,7 @@ int snd_usb_endpoint_prepare(struct snd_usb_audio *chip,
 	ep->iface_ref->need_setup = false;
 
  done:
-	ep->need_setup = false;
+	ep->need_prepare = false;
 	err = 1;
 
 unlock: