Revert "ALSA: usb-audio: Improve frames size computation"

BugLink: https://bugs.launchpad.net/bugs/1887011

This reverts commit 02c56650f3c118d3752122996d96173d26bb13aa which is
commit f0bd62b6 upstream.

It causes a number of reported issues and a fix for it has not hit
Linus's tree yet.  Revert this to resolve those problems.

Cc: Alexander Tsoy <alexander@tsoy.me>
Cc: Takashi Iwai <tiwai@suse.de>
Cc: Sasha Levin <sashal@kernel.org>
Cc: Hans de Goede <jwrdegoede@fedoraproject.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Signed-off-by: Kamal Mostafa <kamal@canonical.com>
Signed-off-by: Kelsey Skunberg <kelsey.skunberg@canonical.com>

sound/usb/card.h

@@ -80,10 +80,6 @@ struct snd_usb_endpoint {
 	dma_addr_t sync_dma;		/* DMA address of syncbuf */
 
 	unsigned int pipe;		/* the data i/o pipe */
-	unsigned int framesize[2];	/* small/large frame sizes in samples */
-	unsigned int sample_rem;	/* remainder from division fs/fps */
-	unsigned int sample_accum;	/* sample accumulator */
-	unsigned int fps;		/* frames per second */
 	unsigned int freqn;		/* nominal sampling rate in fs/fps in Q16.16 format */
 	unsigned int freqm;		/* momentary sampling rate in fs/fps in Q16.16 format */
 	int	   freqshift;		/* how much to shift the feedback value to get Q16.16 */

sound/usb/endpoint.c

@@ -137,12 +137,12 @@ int snd_usb_endpoint_implicit_feedback_sink(struct snd_usb_endpoint *ep)
 
 /*
  * For streaming based on information derived from sync endpoints,
- * prepare_outbound_urb_sizes() will call slave_next_packet_size() to
+ * prepare_outbound_urb_sizes() will call next_packet_size() to
  * determine the number of samples to be sent in the next packet.
  *
- * For implicit feedback, slave_next_packet_size() is unused.
+ * For implicit feedback, next_packet_size() is unused.
  */
-int snd_usb_endpoint_slave_next_packet_size(struct snd_usb_endpoint *ep)
+int snd_usb_endpoint_next_packet_size(struct snd_usb_endpoint *ep)
 {
 	unsigned long flags;
 	int ret;
@@ -159,29 +159,6 @@ int snd_usb_endpoint_slave_next_packet_size(struct snd_usb_endpoint *ep)
 	return ret;
 }
 
-/*
- * For adaptive and synchronous endpoints, prepare_outbound_urb_sizes()
- * will call next_packet_size() to determine the number of samples to be
- * sent in the next packet.
- */
-int snd_usb_endpoint_next_packet_size(struct snd_usb_endpoint *ep)
-{
-	int ret;
-
-	if (ep->fill_max)
-		return ep->maxframesize;
-
-	ep->sample_accum += ep->sample_rem;
-	if (ep->sample_accum >= ep->fps) {
-		ep->sample_accum -= ep->fps;
-		ret = ep->framesize[1];
-	} else {
-		ret = ep->framesize[0];
-	}
-
-	return ret;
-}
-
 static void retire_outbound_urb(struct snd_usb_endpoint *ep,
 				struct snd_urb_ctx *urb_ctx)
 {
@@ -226,8 +203,6 @@ static void prepare_silent_urb(struct snd_usb_endpoint *ep,
 
 		if (ctx->packet_size[i])
 			counts = ctx->packet_size[i];
-		else if (ep->sync_master)
-			counts = snd_usb_endpoint_slave_next_packet_size(ep);
 		else
 			counts = snd_usb_endpoint_next_packet_size(ep);
 
@@ -904,17 +879,10 @@ int snd_usb_endpoint_set_params(struct snd_usb_endpoint *ep,
 	ep->maxpacksize = fmt->maxpacksize;
 	ep->fill_max = !!(fmt->attributes & UAC_EP_CS_ATTR_FILL_MAX);
 
-	if (snd_usb_get_speed(ep->chip->dev) == USB_SPEED_FULL) {
+	if (snd_usb_get_speed(ep->chip->dev) == USB_SPEED_FULL)
 		ep->freqn = get_usb_full_speed_rate(rate);
-		ep->fps = 1000;
-	} else {
+	else
 		ep->freqn = get_usb_high_speed_rate(rate);
-		ep->fps = 8000;
-	}
-
-	ep->sample_rem = rate % ep->fps;
-	ep->framesize[0] = rate / ep->fps;
-	ep->framesize[1] = (rate + (ep->fps - 1)) / ep->fps;
 
 	/* calculate the frequency in 16.16 format */
 	ep->freqm = ep->freqn;
@@ -973,7 +941,6 @@ int snd_usb_endpoint_start(struct snd_usb_endpoint *ep)
 	ep->active_mask = 0;
 	ep->unlink_mask = 0;
 	ep->phase = 0;
-	ep->sample_accum = 0;
 
 	snd_usb_endpoint_start_quirk(ep);
 

sound/usb/endpoint.h

@@ -27,7 +27,6 @@ void snd_usb_endpoint_release(struct snd_usb_endpoint *ep);
 void snd_usb_endpoint_free(struct snd_usb_endpoint *ep);
 
 int snd_usb_endpoint_implicit_feedback_sink(struct snd_usb_endpoint *ep);
-int snd_usb_endpoint_slave_next_packet_size(struct snd_usb_endpoint *ep);
 int snd_usb_endpoint_next_packet_size(struct snd_usb_endpoint *ep);
 
 void snd_usb_handle_sync_urb(struct snd_usb_endpoint *ep,

sound/usb/pcm.c

@@ -1473,8 +1473,6 @@ static void prepare_playback_urb(struct snd_usb_substream *subs,
 	for (i = 0; i < ctx->packets; i++) {
 		if (ctx->packet_size[i])
 			counts = ctx->packet_size[i];
-		else if (ep->sync_master)
-			counts = snd_usb_endpoint_slave_next_packet_size(ep);
 		else
 			counts = snd_usb_endpoint_next_packet_size(ep);