---------------------
PatchSet 3151 
Date: 2005/05/02 08:55:54
Author: cladisch
Branch: HEAD
Tag: (none) 
Log:
Summary: usb-audio - use only one packet in synchronization feedback URBs

Do not use more than one packet in synchronization feedback URBs because
it would be pointless to send or receive more than one value at the same
time.

Members: 
	usb/usbaudio.c:1.126->1.127 

Index: /sound/usb/usbaudio.c
diff -u /sound/usb/usbaudio.c.old /sound/usb/usbaudio.c
--- /sound/usb/usbaudio.c.old	Mon May  2 00:53:46 2005
+++ /sound/usb/usbaudio.c	Mon May  2 00:55:54 2005
@@ -177,7 +177,7 @@
 	unsigned int nurbs;			/* # urbs */
 	snd_urb_ctx_t dataurb[MAX_URBS];	/* data urb table */
 	snd_urb_ctx_t syncurb[SYNC_URBS];	/* sync urb table */
-	char syncbuf[SYNC_URBS * MAX_PACKS * 4]; /* sync buffer; it's so small - let's get static */
+	char syncbuf[SYNC_URBS * 4];	/* sync buffer; it's so small - let's get static */
 	char *tmpbuf;			/* temporary buffer for playback */
 
 	u64 formats;			/* format bitmasks (all or'ed) */
@@ -251,17 +251,13 @@
 {
 	unsigned char *cp = urb->transfer_buffer;
 	snd_urb_ctx_t *ctx = (snd_urb_ctx_t *)urb->context;
-	int i, offs;
 
-	urb->number_of_packets = ctx->packets;
 	urb->dev = ctx->subs->dev; /* we need to set this at each time */
-	for (i = offs = 0; i < urb->number_of_packets; i++, offs += 4, cp += 4) {
-		urb->iso_frame_desc[i].length = 3;
-		urb->iso_frame_desc[i].offset = offs;
-		cp[0] = subs->freqn >> 2;
-		cp[1] = subs->freqn >> 10;
-		cp[2] = subs->freqn >> 18;
-	}
+	urb->iso_frame_desc[0].length = 3;
+	urb->iso_frame_desc[0].offset = 0;
+	cp[0] = subs->freqn >> 2;
+	cp[1] = subs->freqn >> 10;
+	cp[2] = subs->freqn >> 18;
 	return 0;
 }
 
@@ -277,18 +273,14 @@
 {
 	unsigned char *cp = urb->transfer_buffer;
 	snd_urb_ctx_t *ctx = (snd_urb_ctx_t *)urb->context;
-	int i, offs;
 
-	urb->number_of_packets = ctx->packets;
 	urb->dev = ctx->subs->dev; /* we need to set this at each time */
-	for (i = offs = 0; i < urb->number_of_packets; i++, offs += 4, cp += 4) {
-		urb->iso_frame_desc[i].length = 4;
-		urb->iso_frame_desc[i].offset = offs;
-		cp[0] = subs->freqn;
-		cp[1] = subs->freqn >> 8;
-		cp[2] = subs->freqn >> 16;
-		cp[3] = subs->freqn >> 24;
-	}
+	urb->iso_frame_desc[0].length = 4;
+	urb->iso_frame_desc[0].offset = 0;
+	cp[0] = subs->freqn;
+	cp[1] = subs->freqn >> 8;
+	cp[2] = subs->freqn >> 16;
+	cp[3] = subs->freqn >> 24;
 	return 0;
 }
 
@@ -418,15 +410,11 @@
 				     snd_pcm_runtime_t *runtime,
 				     struct urb *urb)
 {
-	int i, offs;
 	snd_urb_ctx_t *ctx = (snd_urb_ctx_t *)urb->context;
 
-	urb->number_of_packets = ctx->packets;
 	urb->dev = ctx->subs->dev; /* we need to set this at each time */
-	for (i = offs = 0; i < urb->number_of_packets; i++, offs += 4) {
-		urb->iso_frame_desc[i].length = 3;
-		urb->iso_frame_desc[i].offset = offs;
-	}
+	urb->iso_frame_desc[0].length = 3;
+	urb->iso_frame_desc[0].offset = 0;
 	return 0;
 }
 
@@ -440,15 +428,11 @@
 					snd_pcm_runtime_t *runtime,
 					struct urb *urb)
 {
-	int i, offs;
 	snd_urb_ctx_t *ctx = (snd_urb_ctx_t *)urb->context;
 
-	urb->number_of_packets = ctx->packets;
 	urb->dev = ctx->subs->dev; /* we need to set this at each time */
-	for (i = offs = 0; i < urb->number_of_packets; i++, offs += 4) {
-		urb->iso_frame_desc[i].length = 4;
-		urb->iso_frame_desc[i].offset = offs;
-	}
+	urb->iso_frame_desc[0].length = 4;
+	urb->iso_frame_desc[0].offset = 0;
 	return 0;
 }
 
@@ -462,17 +446,12 @@
 				    snd_pcm_runtime_t *runtime,
 				    struct urb *urb)
 {
-	int i;
-	unsigned int f, found;
-	unsigned char *cp = urb->transfer_buffer;
+	unsigned int f;
 	unsigned long flags;
 
-	found = 0;
-	for (i = 0; i < urb->number_of_packets; i++, cp += 4) {
-		if (urb->iso_frame_desc[i].status ||
-		    urb->iso_frame_desc[i].actual_length < 3)
-			continue;
-		f = combine_triple(cp) << 2;
+	if (urb->iso_frame_desc[0].status == 0 &&
+	    urb->iso_frame_desc[0].actual_length == 3) {
+		f = combine_triple((u8*)urb->transfer_buffer) << 2;
 #if 0
 		if (f < subs->freqn - (subs->freqn>>3) || f > subs->freqmax) {
 			snd_printd(KERN_WARNING "requested frequency %d (%u,%03uHz) out of range (current nominal %d (%u,%03uHz))\n",
@@ -481,11 +460,8 @@
 			continue;
 		}
 #endif
-		found = f;
-	}
-	if (found) {
 		spin_lock_irqsave(&subs->lock, flags);
-		subs->freqm = found;
+		subs->freqm = f;
 		spin_unlock_irqrestore(&subs->lock, flags);
 	}
 
@@ -502,21 +478,14 @@
 				       snd_pcm_runtime_t *runtime,
 				       struct urb *urb)
 {
-	int i;
-	unsigned int found;
-	unsigned char *cp = urb->transfer_buffer;
+	unsigned int f;
 	unsigned long flags;
 
-	found = 0;
-	for (i = 0; i < urb->number_of_packets; i++, cp += 4) {
-		if (urb->iso_frame_desc[i].status ||
-		    urb->iso_frame_desc[i].actual_length < 4)
-			continue;
-		found = combine_quad(cp) & 0x0fffffff;
-	}
-	if (found) {
+	if (urb->iso_frame_desc[0].status == 0 &&
+	    urb->iso_frame_desc[0].actual_length == 4) {
+		f = combine_quad((u8*)urb->transfer_buffer) & 0x0fffffff;
 		spin_lock_irqsave(&subs->lock, flags);
-		subs->freqm = found;
+		subs->freqm = f;
 		spin_unlock_irqrestore(&subs->lock, flags);
 	}
 
@@ -1039,18 +1008,18 @@
 			snd_urb_ctx_t *u = &subs->syncurb[i];
 			u->index = i;
 			u->subs = subs;
-			u->packets = nrpacks;
-			u->urb = usb_alloc_urb(u->packets, GFP_KERNEL);
+			u->packets = 1;
+			u->urb = usb_alloc_urb(1, GFP_KERNEL);
 			if (! u->urb) {
 				release_substream_urbs(subs, 0);
 				return -ENOMEM;
 			}
-			u->urb->transfer_buffer = subs->syncbuf + i * nrpacks * 4;
-			u->urb->transfer_buffer_length = nrpacks * 4;
+			u->urb->transfer_buffer = subs->syncbuf + i * 4;
+			u->urb->transfer_buffer_length = 4;
 			u->urb->dev = subs->dev;
 			u->urb->pipe = subs->syncpipe;
 			u->urb->transfer_flags = URB_ISO_ASAP;
-			u->urb->number_of_packets = u->packets;
+			u->urb->number_of_packets = 1;
 			u->urb->interval = 1 << subs->syncinterval;
 			u->urb->context = u;
 			u->urb->complete = snd_usb_complete_callback(snd_complete_sync_urb);