diff -upNr oldtree/drivers/media/video/gspca/stv06xx/stv06xx.c linux/drivers/media/video/gspca/stv06xx/stv06xx.c
--- oldtree/drivers/media/video/gspca/stv06xx/stv06xx.c	2010-11-09 12:41:28.000000000 -0200
+++ linux/drivers/media/video/gspca/stv06xx/stv06xx.c	2010-11-09 12:41:24.000000000 -0200
@@ -263,7 +263,21 @@ static int stv06xx_init(struct gspca_dev
 static int stv06xx_start(struct gspca_dev *gspca_dev)
 {
 	struct sd *sd = (struct sd *) gspca_dev;
-	int err;
+	struct usb_host_interface *alt;
+	struct usb_interface *intf;
+	int err, packet_size;
+
+	intf = usb_ifnum_to_if(sd->gspca_dev.dev, sd->gspca_dev.iface);
+	alt = usb_altnum_to_altsetting(intf, sd->gspca_dev.alt);
+	if (!alt) {
+		PDEBUG(D_ERR, "Couldn't get altsetting");
+		return -EIO;
+	}
+
+	packet_size = le16_to_cpu(alt->endpoint[0].desc.wMaxPacketSize);
+	err = stv06xx_write_bridge(sd, STV_ISO_SIZE_L, packet_size);
+	if (err < 0)
+		return err;
 
 	/* Prepare the sensor for start */
 	err = sd->sensor->start(sd);
@@ -282,6 +296,43 @@ out:
 	return (err < 0) ? err : 0;
 }
 
+static int stv06xx_isoc_init(struct gspca_dev *gspca_dev)
+{
+	struct usb_host_interface *alt;
+	struct sd *sd = (struct sd *) gspca_dev;
+
+	/* Start isoc bandwidth "negotiation" at max isoc bandwidth */
+	alt = &gspca_dev->dev->config->intf_cache[0]->altsetting[1];
+	alt->endpoint[0].desc.wMaxPacketSize =
+		cpu_to_le16(sd->sensor->max_packet_size[gspca_dev->curr_mode]);
+
+	return 0;
+}
+
+static int stv06xx_isoc_nego(struct gspca_dev *gspca_dev)
+{
+	int ret, packet_size, min_packet_size;
+	struct usb_host_interface *alt;
+	struct sd *sd = (struct sd *) gspca_dev;
+
+	alt = &gspca_dev->dev->config->intf_cache[0]->altsetting[1];
+	packet_size = le16_to_cpu(alt->endpoint[0].desc.wMaxPacketSize);
+	min_packet_size = sd->sensor->min_packet_size[gspca_dev->curr_mode];
+	if (packet_size <= min_packet_size)
+		return -EIO;
+
+	packet_size -= 100;
+	if (packet_size < min_packet_size)
+		packet_size = min_packet_size;
+	alt->endpoint[0].desc.wMaxPacketSize = cpu_to_le16(packet_size);
+
+	ret = usb_set_interface(gspca_dev->dev, gspca_dev->iface, 1);
+	if (ret < 0)
+		PDEBUG(D_ERR|D_STREAM, "set alt 1 err %d", ret);
+
+	return ret;
+}
+
 static void stv06xx_stopN(struct gspca_dev *gspca_dev)
 {
 	int err;
@@ -462,6 +513,8 @@ static const struct sd_desc sd_desc = {
 	.start = stv06xx_start,
 	.stopN = stv06xx_stopN,
 	.pkt_scan = stv06xx_pkt_scan,
+	.isoc_init = stv06xx_isoc_init,
+	.isoc_nego = stv06xx_isoc_nego,
 #ifdef CONFIG_INPUT
 	.int_pkt_scan = sd_int_pkt_scan,
 #endif
diff -upNr oldtree/drivers/media/video/gspca/stv06xx/stv06xx_hdcs.h linux/drivers/media/video/gspca/stv06xx/stv06xx_hdcs.h
--- oldtree/drivers/media/video/gspca/stv06xx/stv06xx_hdcs.h	2010-11-09 12:41:28.000000000 -0200
+++ linux/drivers/media/video/gspca/stv06xx/stv06xx_hdcs.h	2010-11-09 12:41:24.000000000 -0200
@@ -146,6 +146,11 @@ const struct stv06xx_sensor stv06xx_sens
 	.i2c_addr = (0x55 << 1),
 	.i2c_len = 1,
 
+	/* FIXME (see if we can lower min_packet_size, needs testing, and also
+	   adjusting framerate when the bandwidth gets lower) */
+	.min_packet_size = { 847 },
+	.max_packet_size = { 847 },
+
 	.init = hdcs_init,
 	.probe = hdcs_probe_1x00,
 	.start = hdcs_start,
@@ -160,6 +165,11 @@ const struct stv06xx_sensor stv06xx_sens
 	.i2c_addr = (0x55 << 1),
 	.i2c_len = 1,
 
+	/* FIXME (see if we can lower min_packet_size, needs testing, and also
+	   adjusting framerate when the bandwidthm gets lower) */
+	.min_packet_size = { 847 },
+	.max_packet_size = { 847 },
+
 	.init = hdcs_init,
 	.probe = hdcs_probe_1020,
 	.start = hdcs_start,
@@ -177,7 +187,6 @@ static const u16 stv_bridge_init[][2] = 
 	{STV_REG04, 0x07},
 
 	{STV_SCAN_RATE, 0x20},
-	{STV_ISO_SIZE_L, 847},
 	{STV_Y_CTRL, 0x01},
 	{STV_X_CTRL, 0x0a}
 };
diff -upNr oldtree/drivers/media/video/gspca/stv06xx/stv06xx_pb0100.c linux/drivers/media/video/gspca/stv06xx/stv06xx_pb0100.c
--- oldtree/drivers/media/video/gspca/stv06xx/stv06xx_pb0100.c	2010-11-09 12:41:28.000000000 -0200
+++ linux/drivers/media/video/gspca/stv06xx/stv06xx_pb0100.c	2010-11-09 12:41:24.000000000 -0200
@@ -208,11 +208,24 @@ static int pb0100_probe(struct sd *sd)
 
 static int pb0100_start(struct sd *sd)
 {
-	int err;
+	int err, packet_size, max_packet_size;
+	struct usb_host_interface *alt;
+	struct usb_interface *intf;
 	struct cam *cam = &sd->gspca_dev.cam;
 	s32 *sensor_settings = sd->sensor_priv;
 	u32 mode = cam->cam_mode[sd->gspca_dev.curr_mode].priv;
 
+	intf = usb_ifnum_to_if(sd->gspca_dev.dev, sd->gspca_dev.iface);
+	alt = usb_altnum_to_altsetting(intf, sd->gspca_dev.alt);
+	packet_size = le16_to_cpu(alt->endpoint[0].desc.wMaxPacketSize);
+
+	/* If we don't have enough bandwidth use a lower framerate */
+	max_packet_size = sd->sensor->max_packet_size[sd->gspca_dev.curr_mode];
+	if (packet_size < max_packet_size)
+		stv06xx_write_sensor(sd, PB_ROWSPEED, BIT(4)|BIT(3)|BIT(1));
+	else
+		stv06xx_write_sensor(sd, PB_ROWSPEED, BIT(5)|BIT(3)|BIT(1));
+
 	/* Setup sensor window */
 	if (mode & PB0100_CROP_TO_VGA) {
 		stv06xx_write_sensor(sd, PB_RSTART, 30);
@@ -328,9 +341,6 @@ static int pb0100_init(struct sd *sd)
 	stv06xx_write_bridge(sd, STV_REG03, 0x45);
 	stv06xx_write_bridge(sd, STV_REG04, 0x07);
 
-	/* ISO-Size (0x27b: 635... why? - HDCS uses 847) */
-	stv06xx_write_bridge(sd, STV_ISO_SIZE_L, 847);
-
 	/* Scan/timing for the sensor */
 	stv06xx_write_sensor(sd, PB_ROWSPEED, BIT(4)|BIT(3)|BIT(1));
 	stv06xx_write_sensor(sd, PB_CFILLIN, 14);
diff -upNr oldtree/drivers/media/video/gspca/stv06xx/stv06xx_pb0100.h linux/drivers/media/video/gspca/stv06xx/stv06xx_pb0100.h
--- oldtree/drivers/media/video/gspca/stv06xx/stv06xx_pb0100.h	2010-11-09 12:41:28.000000000 -0200
+++ linux/drivers/media/video/gspca/stv06xx/stv06xx_pb0100.h	2010-11-09 12:41:24.000000000 -0200
@@ -138,6 +138,9 @@ const struct stv06xx_sensor stv06xx_sens
 	.i2c_addr = 0xba,
 	.i2c_len = 2,
 
+	.min_packet_size = { 635, 847 },
+	.max_packet_size = { 847, 923 },
+
 	.init = pb0100_init,
 	.probe = pb0100_probe,
 	.start = pb0100_start,
diff -upNr oldtree/drivers/media/video/gspca/stv06xx/stv06xx_sensor.h linux/drivers/media/video/gspca/stv06xx/stv06xx_sensor.h
--- oldtree/drivers/media/video/gspca/stv06xx/stv06xx_sensor.h	2010-11-09 12:41:28.000000000 -0200
+++ linux/drivers/media/video/gspca/stv06xx/stv06xx_sensor.h	2010-11-09 12:41:24.000000000 -0200
@@ -53,6 +53,10 @@ struct stv06xx_sensor {
 	/* length of an i2c word */
 	u8 i2c_len;
 
+	/* Isoc packet size (per mode) */
+	int min_packet_size[4];
+	int max_packet_size[4];
+
 	/* Probes if the sensor is connected */
 	int (*probe)(struct sd *sd);
 
diff -upNr oldtree/drivers/media/video/gspca/stv06xx/stv06xx_st6422.c linux/drivers/media/video/gspca/stv06xx/stv06xx_st6422.c
--- oldtree/drivers/media/video/gspca/stv06xx/stv06xx_st6422.c	2010-11-09 12:41:28.000000000 -0200
+++ linux/drivers/media/video/gspca/stv06xx/stv06xx_st6422.c	2010-11-09 12:41:24.000000000 -0200
@@ -213,7 +213,6 @@ static int st6422_init(struct sd *sd)
 		{ 0x150e, 0x8e },
 		{ 0x150f, 0x37 },
 		{ 0x15c0, 0x00 },
-		{ 0x15c1, 1023 }, /* 160x120, ISOC_PACKET_SIZE */
 		{ 0x15c3, 0x08 },	/* 0x04/0x14 ... test pictures ??? */
 
 
@@ -237,23 +236,9 @@ static void st6422_disconnect(struct sd 
 
 static int st6422_start(struct sd *sd)
 {
-	int err, packet_size;
+	int err;
 	struct cam *cam = &sd->gspca_dev.cam;
 	s32 *sensor_settings = sd->sensor_priv;
-	struct usb_host_interface *alt;
-	struct usb_interface *intf;
-
-	intf = usb_ifnum_to_if(sd->gspca_dev.dev, sd->gspca_dev.iface);
-	alt = usb_altnum_to_altsetting(intf, sd->gspca_dev.alt);
-	if (!alt) {
-		PDEBUG(D_ERR, "Couldn't get altsetting");
-		return -EIO;
-	}
-
-	packet_size = le16_to_cpu(alt->endpoint[0].desc.wMaxPacketSize);
-	err = stv06xx_write_bridge(sd, 0x15c1, packet_size);
-	if (err < 0)
-		return err;
 
 	if (cam->cam_mode[sd->gspca_dev.curr_mode].priv)
 		err = stv06xx_write_bridge(sd, 0x1505, 0x0f);
diff -upNr oldtree/drivers/media/video/gspca/stv06xx/stv06xx_st6422.h linux/drivers/media/video/gspca/stv06xx/stv06xx_st6422.h
--- oldtree/drivers/media/video/gspca/stv06xx/stv06xx_st6422.h	2010-11-09 12:41:28.000000000 -0200
+++ linux/drivers/media/video/gspca/stv06xx/stv06xx_st6422.h	2010-11-09 12:41:24.000000000 -0200
@@ -49,6 +49,9 @@ static int st6422_set_exposure(struct gs
 
 const struct stv06xx_sensor stv06xx_sensor_st6422 = {
 	.name = "ST6422",
+	/* No known way to lower framerate in case of less bandwidth */
+	.min_packet_size = { 300, 847 },
+	.max_packet_size = { 300, 847 },
 	.init = st6422_init,
 	.probe = st6422_probe,
 	.start = st6422_start,
diff -upNr oldtree/drivers/media/video/gspca/stv06xx/stv06xx_vv6410.h linux/drivers/media/video/gspca/stv06xx/stv06xx_vv6410.h
--- oldtree/drivers/media/video/gspca/stv06xx/stv06xx_vv6410.h	2010-11-09 12:41:28.000000000 -0200
+++ linux/drivers/media/video/gspca/stv06xx/stv06xx_vv6410.h	2010-11-09 12:41:24.000000000 -0200
@@ -197,6 +197,10 @@ const struct stv06xx_sensor stv06xx_sens
 	.i2c_flush = 5,
 	.i2c_addr = 0x20,
 	.i2c_len = 1,
+	/* FIXME (see if we can lower packet_size-s, needs testing, and also
+	   adjusting framerate when the bandwidth gets lower) */
+	.min_packet_size = { 1023 },
+	.max_packet_size = { 1023 },
 	.init = vv6410_init,
 	.probe = vv6410_probe,
 	.start = vv6410_start,
@@ -220,10 +224,6 @@ static const u8 x1536[] = {	/* 0x1536 - 
 	0x02, 0x00, 0x60, 0x01, 0x20, 0x01
 };
 
-static const u8 x15c1[] = {	/* 0x15c1 - 0x15c2 */
-	0xff, 0x03 /* Output word 0x03ff = 1023 (ISO size) */
-};
-
 static const struct stv_init stv_bridge_init[] = {
 	/* This reg is written twice. Some kind of reset? */
 	{NULL,  0x1620, 0x80},
@@ -232,7 +232,6 @@ static const struct stv_init stv_bridge_
 	{NULL,  0x1423, 0x04},
 	{x1500, 0x1500, ARRAY_SIZE(x1500)},
 	{x1536, 0x1536, ARRAY_SIZE(x1536)},
-	{x15c1, 0x15c1, ARRAY_SIZE(x15c1)}
 };
 
 static const u8 vv6410_sensor_init[][2] = {
