Don't use stack for DMA transers on media usb drivers

index efa782ed6e2d..4883f2fb4c2d 100644
@@ -52,17 +52,16 @@ u8 regmask[8] = { 0x01, 0x03, 0x07, 0x0f, 0x1f, 0x3f, 0x7f, 0xff };
 struct af9005_device_state {
 	u8 sequence;
 	int led_state;
+	unsigned char data[256];
+	struct mutex data_mutex;
 };
 
 static int af9005_generic_read_write(struct dvb_usb_device *d, u16 reg,
 			      int readwrite, int type, u8 * values, int len)
 {
 	struct af9005_device_state *st = d->priv;
-	u8 obuf[16] = { 0 };
-	u8 ibuf[17] = { 0 };
-	u8 command;
-	int i;
-	int ret;
+	u8 command, seq;
+	int i, ret;
 
 	if (len < 1) {
 		err("generic read/write, less than 1 byte. Makes no sense.");

@@ -73,16 +72,17 @@ static int af9005_generic_read_write(struct dvb_usb_device *d, u16 reg,
 		return -EINVAL;
 	}
 
-	obuf[0] = 14;		/* rest of buffer length low */
-	obuf[1] = 0;		/* rest of buffer length high */
+	mutex_lock(&st->data_mutex);
+	st->data[0] = 14;		/* rest of buffer length low */
+	st->data[1] = 0;		/* rest of buffer length high */
 
-	obuf[2] = AF9005_REGISTER_RW;	/* register operation */
-	obuf[3] = 12;		/* rest of buffer length */
+	st->data[2] = AF9005_REGISTER_RW;	/* register operation */
+	st->data[3] = 12;		/* rest of buffer length */
 
-	obuf[4] = st->sequence++;	/* sequence number */
+	st->data[4] = seq = st->sequence++;	/* sequence number */
 
-	obuf[5] = (u8) (reg >> 8);	/* register address */
-	obuf[6] = (u8) (reg & 0xff);
+	st->data[5] = (u8) (reg >> 8);	/* register address */
+	st->data[6] = (u8) (reg & 0xff);
 
 	if (type == AF9005_OFDM_REG) {
 		command = AF9005_CMD_OFDM_REG;

@@ -96,51 +96,52 @@ static int af9005_generic_read_write(struct dvb_usb_device *d, u16 reg,
 	command |= readwrite;
 	if (readwrite == AF9005_CMD_WRITE)
 		for (i = 0; i < len; i++)
-			obuf[8 + i] = values[i];
+			st->data[8 + i] = values[i];
 	else if (type == AF9005_TUNER_REG)
 		/* read command for tuner, the first byte contains the i2c address */
-		obuf[8] = values[0];
-	obuf[7] = command;
+		st->data[8] = values[0];
+	st->data[7] = command;
 
-	ret = dvb_usb_generic_rw(d, obuf, 16, ibuf, 17, 0);
+	ret = dvb_usb_generic_rw(d, st->data, 16, st->data, 17, 0);
 	if (ret)
-		return ret;
+		goto ret;
 
 	/* sanity check */
-	if (ibuf[2] != AF9005_REGISTER_RW_ACK) {
+	if (st->data[2] != AF9005_REGISTER_RW_ACK) {
 		err("generic read/write, wrong reply code.");
-		return -EIO;
+		ret = -EIO;
+		goto ret;
 	}
-	if (ibuf[3] != 0x0d) {
+	if (st->data[3] != 0x0d) {
 		err("generic read/write, wrong length in reply.");
-		return -EIO;
+		ret = -EIO;
+		goto ret;
 	}
-	if (ibuf[4] != obuf[4]) {
+	if (st->data[4] != seq) {
 		err("generic read/write, wrong sequence in reply.");
-		return -EIO;
+		ret = -EIO;
+		goto ret;
 	}
 	/*
-	   Windows driver doesn't check these fields, in fact sometimes
-	   the register in the reply is different that what has been sent
-
-	   if (ibuf[5] != obuf[5] || ibuf[6] != obuf[6]) {
-	   err("generic read/write, wrong register in reply.");
-	   return -EIO;
-	   }
-	   if (ibuf[7] != command) {
-	   err("generic read/write wrong command in reply.");
-	   return -EIO;
-	   }
+	 * In thesis, both input and output buffers should have
+	 * identical values for st->data[5] to st->data[8].
+	 * However, windows driver doesn't check these fields, in fact
+	 * sometimes the register in the reply is different that what
+	 * has been sent
 	 */
-	if (ibuf[16] != 0x01) {
+	if (st->data[16] != 0x01) {
 		err("generic read/write wrong status code in reply.");
-		return -EIO;
+		ret = -EIO;
+		goto ret;
 	}
+
 	if (readwrite == AF9005_CMD_READ)
 		for (i = 0; i < len; i++)
-			values[i] = ibuf[8 + i];
+			values[i] = st->data[8 + i];
 
-	return 0;
+ret:
+	mutex_unlock(&st->data_mutex);
+	return ret;
 
 }
 

@@ -464,8 +465,7 @@ int af9005_send_command(struct dvb_usb_device *d, u8 command, u8 * wbuf,
 	struct af9005_device_state *st = d->priv;
 
 	int ret, i, packet_len;
-	u8 buf[64];
-	u8 ibuf[64];
+	u8 seq;
 
 	if (wlen < 0) {
 		err("send command, wlen less than 0 bytes. Makes no sense.");

@@ -480,94 +480,97 @@ int af9005_send_command(struct dvb_usb_device *d, u8 command, u8 * wbuf,
 		return -EINVAL;
 	}
 	packet_len = wlen + 5;
-	buf[0] = (u8) (packet_len & 0xff);
-	buf[1] = (u8) ((packet_len & 0xff00) >> 8);
 
-	buf[2] = 0x26;		/* packet type */
-	buf[3] = wlen + 3;
-	buf[4] = st->sequence++;
-	buf[5] = command;
-	buf[6] = wlen;
+	mutex_lock(&st->data_mutex);
+
+	st->data[0] = (u8) (packet_len & 0xff);
+	st->data[1] = (u8) ((packet_len & 0xff00) >> 8);
+
+	st->data[2] = 0x26;		/* packet type */
+	st->data[3] = wlen + 3;
+	st->data[4] = seq = st->sequence++;
+	st->data[5] = command;
+	st->data[6] = wlen;
 	for (i = 0; i < wlen; i++)
-		buf[7 + i] = wbuf[i];
-	ret = dvb_usb_generic_rw(d, buf, wlen + 7, ibuf, rlen + 7, 0);
-	if (ret)
-		return ret;
-	if (ibuf[2] != 0x27) {
+		st->data[7 + i] = wbuf[i];
+	ret = dvb_usb_generic_rw(d, st->data, wlen + 7, st->data, rlen + 7, 0);
+	if (st->data[2] != 0x27) {
 		err("send command, wrong reply code.");
-		return -EIO;
-	}
-	if (ibuf[4] != buf[4]) {
+		ret = -EIO;
+	} else if (st->data[4] != seq) {
 		err("send command, wrong sequence in reply.");
-		return -EIO;
-	}
-	if (ibuf[5] != 0x01) {
+		ret = -EIO;
+	} else if (st->data[5] != 0x01) {
 		err("send command, wrong status code in reply.");
-		return -EIO;
-	}
-	if (ibuf[6] != rlen) {
+		ret = -EIO;
+	} else if (st->data[6] != rlen) {
 		err("send command, invalid data length in reply.");
-		return -EIO;
+		ret = -EIO;
 	}
-	for (i = 0; i < rlen; i++)
-		rbuf[i] = ibuf[i + 7];
-	return 0;
+	if (!ret) {
+		for (i = 0; i < rlen; i++)
+			rbuf[i] = st->data[i + 7];
+	}
+
+	mutex_unlock(&st->data_mutex);
+	return ret;
 }
 
 int af9005_read_eeprom(struct dvb_usb_device *d, u8 address, u8 * values,
 		       int len)
 {
 	struct af9005_device_state *st = d->priv;
-	u8 obuf[16], ibuf[14];
+	u8 seq;
 	int ret, i;
 
-	memset(obuf, 0, sizeof(obuf));
-	memset(ibuf, 0, sizeof(ibuf));
+	mutex_lock(&st->data_mutex);
 
-	obuf[0] = 14;		/* length of rest of packet low */
-	obuf[1] = 0;		/* length of rest of packer high */
+	memset(st->data, 0, sizeof(st->data));
 
-	obuf[2] = 0x2a;		/* read/write eeprom */
+	st->data[0] = 14;		/* length of rest of packet low */
+	st->data[1] = 0;		/* length of rest of packer high */
 
-	obuf[3] = 12;		/* size */
+	st->data[2] = 0x2a;		/* read/write eeprom */
 
-	obuf[4] = st->sequence++;
+	st->data[3] = 12;		/* size */
 
-	obuf[5] = 0;		/* read */
+	st->data[4] = seq = st->sequence++;
 
-	obuf[6] = len;
-	obuf[7] = address;
-	ret = dvb_usb_generic_rw(d, obuf, 16, ibuf, 14, 0);
-	if (ret)
-		return ret;
-	if (ibuf[2] != 0x2b) {
+	st->data[5] = 0;		/* read */
+
+	st->data[6] = len;
+	st->data[7] = address;
+	ret = dvb_usb_generic_rw(d, st->data, 16, st->data, 14, 0);
+	if (st->data[2] != 0x2b) {
 		err("Read eeprom, invalid reply code");
-		return -EIO;
-	}
-	if (ibuf[3] != 10) {
+		ret = -EIO;
+	} else if (st->data[3] != 10) {
 		err("Read eeprom, invalid reply length");
-		return -EIO;
-	}
-	if (ibuf[4] != obuf[4]) {
+		ret = -EIO;
+	} else if (st->data[4] != seq) {
 		err("Read eeprom, wrong sequence in reply ");
-		return -EIO;
-	}
-	if (ibuf[5] != 1) {
+		ret = -EIO;
+	} else if (st->data[5] != 1) {
 		err("Read eeprom, wrong status in reply ");
-		return -EIO;
+		ret = -EIO;
 	}
-	for (i = 0; i < len; i++) {
-		values[i] = ibuf[6 + i];
+
+	if (!ret) {
+		for (i = 0; i < len; i++)
+			values[i] = st->data[6 + i];
 	}
-	return 0;
+	mutex_unlock(&st->data_mutex);
+
+	return ret;
 }
 
-static int af9005_boot_packet(struct usb_device *udev, int type, u8 * reply)
+static int af9005_boot_packet(struct usb_device *udev, int type, u8 *reply,
+			      u8 *buf, int size)
 {
-	u8 buf[FW_BULKOUT_SIZE + 2];
 	u16 checksum;
 	int act_len, i, ret;
-	memset(buf, 0, sizeof(buf));
+
+	memset(buf, 0, size);
 	buf[0] = (u8) (FW_BULKOUT_SIZE & 0xff);
 	buf[1] = (u8) ((FW_BULKOUT_SIZE >> 8) & 0xff);
 	switch (type) {

@@ -720,15 +723,21 @@ static int af9005_download_firmware(struct usb_device *udev, const struct firmwa
 {
 	int i, packets, ret, act_len;
 
-	u8 buf[FW_BULKOUT_SIZE + 2];
+	u8 *buf;
 	u8 reply;
 
-	ret = af9005_boot_packet(udev, FW_CONFIG, &reply);
+	buf = kmalloc(FW_BULKOUT_SIZE + 2, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	ret = af9005_boot_packet(udev, FW_CONFIG, &reply, buf,
+				 FW_BULKOUT_SIZE + 2);
 	if (ret)
-		return ret;
+		goto err;
 	if (reply != 0x01) {
 		err("before downloading firmware, FW_CONFIG expected 0x01, received 0x%x", reply);
-		return -EIO;
+		ret = -EIO;
+		goto err;
 	}
 	packets = fw->size / FW_BULKOUT_SIZE;
 	buf[0] = (u8) (FW_BULKOUT_SIZE & 0xff);

@@ -743,28 +752,35 @@ static int af9005_download_firmware(struct usb_device *udev, const struct firmwa
 				   buf, FW_BULKOUT_SIZE + 2, &act_len, 1000);
 		if (ret) {
 			err("firmware download failed at packet %d with code %d", i, ret);
-			return ret;
+			goto err;
 		}
 	}
-	ret = af9005_boot_packet(udev, FW_CONFIRM, &reply);
+	ret = af9005_boot_packet(udev, FW_CONFIRM, &reply,
+				 buf, FW_BULKOUT_SIZE + 2);
 	if (ret)
-		return ret;
+		goto err;
 	if (reply != (u8) (packets & 0xff)) {
 		err("after downloading firmware, FW_CONFIRM expected 0x%x, received 0x%x", packets & 0xff, reply);
-		return -EIO;
+		ret = -EIO;
+		goto err;
 	}
-	ret = af9005_boot_packet(udev, FW_BOOT, &reply);
+	ret = af9005_boot_packet(udev, FW_BOOT, &reply, buf,
+				 FW_BULKOUT_SIZE + 2);
 	if (ret)
-		return ret;
-	ret = af9005_boot_packet(udev, FW_CONFIG, &reply);
+		goto err;
+	ret = af9005_boot_packet(udev, FW_CONFIG, &reply, buf,
+				 FW_BULKOUT_SIZE + 2);
 	if (ret)
-		return ret;
+		goto err;
 	if (reply != 0x02) {
 		err("after downloading firmware, FW_CONFIG expected 0x02, received 0x%x", reply);
-		return -EIO;
+		ret = -EIO;
+		goto err;
 	}
 
-	return 0;
+err:
+	kfree(buf);
+	return ret;
 
 }
 

@@ -823,53 +839,59 @@ static int af9005_rc_query(struct dvb_usb_device *d, u32 * event, int *state)
 {
 	struct af9005_device_state *st = d->priv;
 	int ret, len;
-
-	u8 obuf[5];
-	u8 ibuf[256];
+	u8 seq;
 
 	*state = REMOTE_NO_KEY_PRESSED;
 	if (rc_decode == NULL) {
 		/* it shouldn't never come here */
 		return 0;
 	}
+
+	mutex_lock(&st->data_mutex);
+
 	/* deb_info("rc_query\n"); */
-	obuf[0] = 3;		/* rest of packet length low */
-	obuf[1] = 0;		/* rest of packet lentgh high */
-	obuf[2] = 0x40;		/* read remote */
-	obuf[3] = 1;		/* rest of packet length */
-	obuf[4] = st->sequence++;	/* sequence number */
-	ret = dvb_usb_generic_rw(d, obuf, 5, ibuf, 256, 0);
+	st->data[0] = 3;		/* rest of packet length low */
+	st->data[1] = 0;		/* rest of packet lentgh high */
+	st->data[2] = 0x40;		/* read remote */
+	st->data[3] = 1;		/* rest of packet length */
+	st->data[4] = seq = st->sequence++;	/* sequence number */
+	ret = dvb_usb_generic_rw(d, st->data, 5, st->data, 256, 0);
 	if (ret) {
 		err("rc query failed");
-		return ret;
+		goto ret;
 	}
-	if (ibuf[2] != 0x41) {
+	if (st->data[2] != 0x41) {
 		err("rc query bad header.");
-		return -EIO;
-	}
-	if (ibuf[4] != obuf[4]) {
+		ret = -EIO;
+		goto ret;
+	} else if (st->data[4] != seq) {
 		err("rc query bad sequence.");
-		return -EIO;
+		ret = -EIO;
+		goto ret;
 	}
-	len = ibuf[5];
+	len = st->data[5];
 	if (len > 246) {
 		err("rc query invalid length");
-		return -EIO;
+		ret = -EIO;
+		goto ret;
 	}
 	if (len > 0) {
 		deb_rc("rc data (%d) ", len);
-		debug_dump((ibuf + 6), len, deb_rc);
-		ret = rc_decode(d, &ibuf[6], len, event, state);
+		debug_dump((st->data + 6), len, deb_rc);
+		ret = rc_decode(d, &st->data[6], len, event, state);
 		if (ret) {
 			err("rc_decode failed");
-			return ret;
+			goto ret;
 		} else {
 			deb_rc("rc_decode state %x event %x\n", *state, *event);
 			if (*state == REMOTE_KEY_REPEAT)
 				*event = d->last_event;
 		}
 	}
-	return 0;
+
+ret:
+	mutex_unlock(&st->data_mutex);
+	return ret;
 }
 
 static int af9005_power_ctrl(struct dvb_usb_device *d, int onoff)

@@ -953,10 +975,16 @@ static int af9005_identify_state(struct usb_device *udev,
 				 int *cold)
 {
 	int ret;
-	u8 reply;
-	ret = af9005_boot_packet(udev, FW_CONFIG, &reply);
+	u8 reply, *buf;
+
+	buf = kmalloc(FW_BULKOUT_SIZE + 2, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	ret = af9005_boot_packet(udev, FW_CONFIG, &reply,
+				 buf, FW_BULKOUT_SIZE + 2);
 	if (ret)
-		return ret;
+		goto err;
 	deb_info("result of FW_CONFIG in identify state %d\n", reply);
 	if (reply == 0x01)
 		*cold = 1;

@@ -965,7 +993,10 @@ static int af9005_identify_state(struct usb_device *udev,
 	else
 		return -EIO;
 	deb_info("Identify state cold = %d\n", *cold);
-	return 0;
+
+err:
+	kfree(buf);
+	return ret;
 }
 
 static struct dvb_usb_device_properties af9005_properties;

@@ -973,8 +1004,20 @@ static struct dvb_usb_device_properties af9005_properties;
 static int af9005_usb_probe(struct usb_interface *intf,
 			    const struct usb_device_id *id)
 {
-	return dvb_usb_device_init(intf, &af9005_properties,
-				   THIS_MODULE, NULL, adapter_nr);
+	struct dvb_usb_device *d;
+	struct af9005_device_state *st;
+	int ret;
+
+	ret = dvb_usb_device_init(intf, &af9005_properties,
+			          THIS_MODULE, &d, adapter_nr);
+
+	if (ret < 0)
+		return ret;
+
+	st = d->priv;
+	mutex_init(&st->data_mutex);
+
+	return 0;
 }
 
 enum af9005_usb_table_entry {

index 9fd1527494eb..d85c0c4d4042 100644
@@ -41,6 +41,8 @@ DVB_DEFINE_MOD_OPT_ADAPTER_NR(adapter_nr);
 
 struct cinergyt2_state {
 	u8 rc_counter;
+	unsigned char data[64];
+	struct mutex data_mutex;
 };
 
 /* We are missing a release hook with usb_device data */

@@ -50,33 +52,52 @@ static struct dvb_usb_device_properties cinergyt2_properties;
 
 static int cinergyt2_streaming_ctrl(struct dvb_usb_adapter *adap, int enable)
 {
-	char buf[] = { CINERGYT2_EP1_CONTROL_STREAM_TRANSFER, enable ? 1 : 0 };
-	char result[64];
-	return dvb_usb_generic_rw(adap->dev, buf, sizeof(buf), result,
-				sizeof(result), 0);
+	struct dvb_usb_device *d = adap->dev;
+	struct cinergyt2_state *st = d->priv;
+	int ret;
+
+	mutex_lock(&st->data_mutex);
+	st->data[0] = CINERGYT2_EP1_CONTROL_STREAM_TRANSFER;
+	st->data[1] = enable ? 1 : 0;
+
+	ret = dvb_usb_generic_rw(d, st->data, 2, st->data, 64, 0);
+	mutex_unlock(&st->data_mutex);
+
+	return ret;
 }
 
 static int cinergyt2_power_ctrl(struct dvb_usb_device *d, int enable)
 {
-	char buf[] = { CINERGYT2_EP1_SLEEP_MODE, enable ? 0 : 1 };
-	char state[3];
-	return dvb_usb_generic_rw(d, buf, sizeof(buf), state, sizeof(state), 0);
+	struct cinergyt2_state *st = d->priv;
+	int ret;
+
+	mutex_lock(&st->data_mutex);
+	st->data[0] = CINERGYT2_EP1_SLEEP_MODE;
+	st->data[1] = enable ? 0 : 1;
+
+	ret = dvb_usb_generic_rw(d, st->data, 2, st->data, 3, 0);
+	mutex_unlock(&st->data_mutex);
+
+	return ret;
 }
 
 static int cinergyt2_frontend_attach(struct dvb_usb_adapter *adap)
 {
-	char query[] = { CINERGYT2_EP1_GET_FIRMWARE_VERSION };
-	char state[3];
+	struct dvb_usb_device *d = adap->dev;
+	struct cinergyt2_state *st = d->priv;
 	int ret;
 
 	adap->fe_adap[0].fe = cinergyt2_fe_attach(adap->dev);
 
-	ret = dvb_usb_generic_rw(adap->dev, query, sizeof(query), state,
-				sizeof(state), 0);
+	mutex_lock(&st->data_mutex);
+	st->data[0] = CINERGYT2_EP1_GET_FIRMWARE_VERSION;
+
+	ret = dvb_usb_generic_rw(d, st->data, 1, st->data, 3, 0);
 	if (ret < 0) {
 		deb_rc("cinergyt2_power_ctrl() Failed to retrieve sleep "
 			"state info\n");
 	}
+	mutex_unlock(&st->data_mutex);
 
 	/* Copy this pointer as we are gonna need it in the release phase */
 	cinergyt2_usb_device = adap->dev;

@@ -141,13 +162,16 @@ static int repeatable_keys[] = {
 static int cinergyt2_rc_query(struct dvb_usb_device *d, u32 *event, int *state)
 {
 	struct cinergyt2_state *st = d->priv;
-	u8 key[5] = {0, 0, 0, 0, 0}, cmd = CINERGYT2_EP1_GET_RC_EVENTS;
 	int i;
 
 	*state = REMOTE_NO_KEY_PRESSED;
 
-	dvb_usb_generic_rw(d, &cmd, 1, key, sizeof(key), 0);
-	if (key[4] == 0xff) {
+	mutex_lock(&st->data_mutex);
+	st->data[0] = CINERGYT2_EP1_GET_RC_EVENTS;
+
+	dvb_usb_generic_rw(d, st->data, 1, st->data, 5, 0);
+
+	if (st->data[4] == 0xff) {
 		/* key repeat */
 		st->rc_counter++;
 		if (st->rc_counter > RC_REPEAT_DELAY) {

@@ -157,31 +181,45 @@ static int cinergyt2_rc_query(struct dvb_usb_device *d, u32 *event, int *state)
 					*event = d->last_event;
 					deb_rc("repeat key, event %x\n",
 						   *event);
-					return 0;
+					goto ret;
 				}
 			}
 			deb_rc("repeated key (non repeatable)\n");
 		}
-		return 0;
+		goto ret;
 	}
 
 	/* hack to pass checksum on the custom field */
-	key[2] = ~key[1];
-	dvb_usb_nec_rc_key_to_event(d, key, event, state);
-	if (key[0] != 0) {
+	st->data[2] = ~st->data[1];
+	dvb_usb_nec_rc_key_to_event(d, st->data, event, state);
+	if (st->data[0] != 0) {
 		if (*event != d->last_event)
 			st->rc_counter = 0;
 
-		deb_rc("key: %*ph\n", 5, key);
+		deb_rc("key: %*ph\n", 5, st->data);
 	}
-	return 0;
+
+ret:
+	mutex_unlock(&st->data_mutex);
+	return ret;
 }
 
 static int cinergyt2_usb_probe(struct usb_interface *intf,
 				const struct usb_device_id *id)
 {
-	return dvb_usb_device_init(intf, &cinergyt2_properties,
-					THIS_MODULE, NULL, adapter_nr);
+	struct dvb_usb_device *d;
+	struct cinergyt2_state *st;
+	int ret;
+
+	ret = dvb_usb_device_init(intf, &cinergyt2_properties,
+				  THIS_MODULE, &d, adapter_nr);
+	if (ret < 0)
+		return ret;
+
+	st = d->priv;
+	mutex_init(&st->data_mutex);
+
+	return 0;
 }
 
 

index d85c0c4d4042..2520e30f5338 100644
@@ -102,7 +102,7 @@ static int cinergyt2_frontend_attach(struct dvb_usb_adapter *adap)
 	/* Copy this pointer as we are gonna need it in the release phase */
 	cinergyt2_usb_device = adap->dev;
 
-	return 0;
+	return ret;
 }
 
 static struct rc_map_table rc_map_cinergyt2_table[] = {

@@ -162,14 +162,16 @@ static int repeatable_keys[] = {
 static int cinergyt2_rc_query(struct dvb_usb_device *d, u32 *event, int *state)
 {
 	struct cinergyt2_state *st = d->priv;
-	int i;
+	int i, ret;
 
 	*state = REMOTE_NO_KEY_PRESSED;
 
 	mutex_lock(&st->data_mutex);
 	st->data[0] = CINERGYT2_EP1_GET_RC_EVENTS;
 
-	dvb_usb_generic_rw(d, st->data, 1, st->data, 5, 0);
+	ret = dvb_usb_generic_rw(d, st->data, 1, st->data, 5, 0);
+	if (ret < 0)
+		return ret;
 
 	if (st->data[4] == 0xff) {
 		/* key repeat */

index d85c0c4d4042..8ac825413d5a 100644
@@ -102,7 +102,7 @@ static int cinergyt2_frontend_attach(struct dvb_usb_adapter *adap)
 	/* Copy this pointer as we are gonna need it in the release phase */
 	cinergyt2_usb_device = adap->dev;
 
-	return 0;
+	return ret;
 }
 
 static struct rc_map_table rc_map_cinergyt2_table[] = {

@@ -162,14 +162,16 @@ static int repeatable_keys[] = {
 static int cinergyt2_rc_query(struct dvb_usb_device *d, u32 *event, int *state)
 {
 	struct cinergyt2_state *st = d->priv;
-	int i;
+	int i, ret;
 
 	*state = REMOTE_NO_KEY_PRESSED;
 
 	mutex_lock(&st->data_mutex);
 	st->data[0] = CINERGYT2_EP1_GET_RC_EVENTS;
 
-	dvb_usb_generic_rw(d, st->data, 1, st->data, 5, 0);
+	ret = dvb_usb_generic_rw(d, st->data, 1, st->data, 5, 0);
+	if (ret < 0)
+		goto ret;
 
 	if (st->data[4] == 0xff) {
 		/* key repeat */

index b3ec743a7a2e..fd8edcb56e61 100644
@@ -139,6 +139,7 @@ static uint16_t compute_tps(struct dtv_frontend_properties *op)
 struct cinergyt2_fe_state {
 	struct dvb_frontend fe;
 	struct dvb_usb_device *d;
+	struct dvbt_get_status_msg status;
 };
 
 static int cinergyt2_fe_read_status(struct dvb_frontend *fe,

@@ -154,6 +155,8 @@ static int cinergyt2_fe_read_status(struct dvb_frontend *fe,
 	if (ret < 0)
 		return ret;
 
+	state->status = result;
+
 	*status = 0;
 
 	if (0xffff - le16_to_cpu(result.gain) > 30)

@@ -177,34 +180,16 @@ static int cinergyt2_fe_read_status(struct dvb_frontend *fe,
 static int cinergyt2_fe_read_ber(struct dvb_frontend *fe, u32 *ber)
 {
 	struct cinergyt2_fe_state *state = fe->demodulator_priv;
-	struct dvbt_get_status_msg status;
-	char cmd[] = { CINERGYT2_EP1_GET_TUNER_STATUS };
-	int ret;
 
-	ret = dvb_usb_generic_rw(state->d, cmd, sizeof(cmd), (char *)&status,
-				sizeof(status), 0);
-	if (ret < 0)
-		return ret;
-
-	*ber = le32_to_cpu(status.viterbi_error_rate);
+	*ber = le32_to_cpu(state->status.viterbi_error_rate);
 	return 0;
 }
 
 static int cinergyt2_fe_read_unc_blocks(struct dvb_frontend *fe, u32 *unc)
 {
 	struct cinergyt2_fe_state *state = fe->demodulator_priv;
-	struct dvbt_get_status_msg status;
-	u8 cmd[] = { CINERGYT2_EP1_GET_TUNER_STATUS };
-	int ret;
 
-	ret = dvb_usb_generic_rw(state->d, cmd, sizeof(cmd), (u8 *)&status,
-				sizeof(status), 0);
-	if (ret < 0) {
-		err("cinergyt2_fe_read_unc_blocks() Failed! (Error=%d)\n",
-			ret);
-		return ret;
-	}
-	*unc = le32_to_cpu(status.uncorrected_block_count);
+	*unc = le32_to_cpu(state->status.uncorrected_block_count);
 	return 0;
 }
 

@@ -212,35 +197,16 @@ static int cinergyt2_fe_read_signal_strength(struct dvb_frontend *fe,
 						u16 *strength)
 {
 	struct cinergyt2_fe_state *state = fe->demodulator_priv;
-	struct dvbt_get_status_msg status;
-	char cmd[] = { CINERGYT2_EP1_GET_TUNER_STATUS };
-	int ret;
 
-	ret = dvb_usb_generic_rw(state->d, cmd, sizeof(cmd), (char *)&status,
-				sizeof(status), 0);
-	if (ret < 0) {
-		err("cinergyt2_fe_read_signal_strength() Failed!"
-			" (Error=%d)\n", ret);
-		return ret;
-	}
-	*strength = (0xffff - le16_to_cpu(status.gain));
+	*strength = (0xffff - le16_to_cpu(state->status.gain));
 	return 0;
 }
 
 static int cinergyt2_fe_read_snr(struct dvb_frontend *fe, u16 *snr)
 {
 	struct cinergyt2_fe_state *state = fe->demodulator_priv;
-	struct dvbt_get_status_msg status;
-	char cmd[] = { CINERGYT2_EP1_GET_TUNER_STATUS };
-	int ret;
 
-	ret = dvb_usb_generic_rw(state->d, cmd, sizeof(cmd), (char *)&status,
-				sizeof(status), 0);
-	if (ret < 0) {
-		err("cinergyt2_fe_read_snr() Failed! (Error=%d)\n", ret);
-		return ret;
-	}
-	*snr = (status.snr << 8) | status.snr;
+	*snr = (state->status.snr << 8) | state->status.snr;
 	return 0;
 }
 

index fd8edcb56e61..2d29b4174dba 100644
@@ -139,6 +139,10 @@ static uint16_t compute_tps(struct dtv_frontend_properties *op)
 struct cinergyt2_fe_state {
 	struct dvb_frontend fe;
 	struct dvb_usb_device *d;
+
+	unsigned char data[64];
+	struct mutex data_mutex;
+
 	struct dvbt_get_status_msg status;
 };
 

@@ -146,28 +150,31 @@ static int cinergyt2_fe_read_status(struct dvb_frontend *fe,
 				    enum fe_status *status)
 {
 	struct cinergyt2_fe_state *state = fe->demodulator_priv;
-	struct dvbt_get_status_msg result;
-	u8 cmd[] = { CINERGYT2_EP1_GET_TUNER_STATUS };
 	int ret;
 
-	ret = dvb_usb_generic_rw(state->d, cmd, sizeof(cmd), (u8 *)&result,
-			sizeof(result), 0);
+	mutex_lock(&state->data_mutex);
+	state->data[0] = CINERGYT2_EP1_GET_TUNER_STATUS;
+
+	ret = dvb_usb_generic_rw(state->d, state->data, 1,
+				 state->data, sizeof(state->status), 0);
+	if (!ret)
+		memcpy(&state->status, state->data, sizeof(state->status));
+	mutex_unlock(&state->data_mutex);
+
 	if (ret < 0)
 		return ret;
 
-	state->status = result;
-
 	*status = 0;
 
-	if (0xffff - le16_to_cpu(result.gain) > 30)
+	if (0xffff - le16_to_cpu(state->status.gain) > 30)
 		*status |= FE_HAS_SIGNAL;
-	if (result.lock_bits & (1 << 6))
+	if (state->status.lock_bits & (1 << 6))
 		*status |= FE_HAS_LOCK;
-	if (result.lock_bits & (1 << 5))
+	if (state->status.lock_bits & (1 << 5))
 		*status |= FE_HAS_SYNC;
-	if (result.lock_bits & (1 << 4))
+	if (state->status.lock_bits & (1 << 4))
 		*status |= FE_HAS_CARRIER;
-	if (result.lock_bits & (1 << 1))
+	if (state->status.lock_bits & (1 << 1))
 		*status |= FE_HAS_VITERBI;
 
 	if ((*status & (FE_HAS_CARRIER | FE_HAS_VITERBI | FE_HAS_SYNC)) !=

@@ -232,34 +239,36 @@ static int cinergyt2_fe_set_frontend(struct dvb_frontend *fe)
 {
 	struct dtv_frontend_properties *fep = &fe->dtv_property_cache;
 	struct cinergyt2_fe_state *state = fe->demodulator_priv;
-	struct dvbt_set_parameters_msg param;
-	char result[2];
+	struct dvbt_set_parameters_msg *param;
 	int err;
 
-	param.cmd = CINERGYT2_EP1_SET_TUNER_PARAMETERS;
-	param.tps = cpu_to_le16(compute_tps(fep));
-	param.freq = cpu_to_le32(fep->frequency / 1000);
-	param.flags = 0;
+	mutex_lock(&state->data_mutex);
+
+	param = (void *)state->data;
+	param->cmd = CINERGYT2_EP1_SET_TUNER_PARAMETERS;
+	param->tps = cpu_to_le16(compute_tps(fep));
+	param->freq = cpu_to_le32(fep->frequency / 1000);
+	param->flags = 0;
 
 	switch (fep->bandwidth_hz) {
 	default:
 	case 8000000:
-		param.bandwidth = 8;
+		param->bandwidth = 8;
 		break;
 	case 7000000:
-		param.bandwidth = 7;
+		param->bandwidth = 7;
 		break;
 	case 6000000:
-		param.bandwidth = 6;
+		param->bandwidth = 6;
 		break;
 	}
 
-	err = dvb_usb_generic_rw(state->d,
-			(char *)&param, sizeof(param),
-			result, sizeof(result), 0);
+	err = dvb_usb_generic_rw(state->d, state->data, sizeof(*param),
+				 state->data, 2, 0);
 	if (err < 0)
 		err("cinergyt2_fe_set_frontend() Failed! err=%d\n", err);
 
+	mutex_unlock(&state->data_mutex);
 	return (err < 0) ? err : 0;
 }
 

@@ -281,6 +290,7 @@ struct dvb_frontend *cinergyt2_fe_attach(struct dvb_usb_device *d)
 	s->d = d;
 	memcpy(&s->fe.ops, &cinergyt2_fe_ops, sizeof(struct dvb_frontend_ops));
 	s->fe.demodulator_priv = s;
+	mutex_init(&s->data_mutex);
 	return &s->fe;
 }
 

index 907ac01ae297..39772812269d 100644
@@ -45,9 +45,6 @@
 #include "si2168.h"
 #include "si2157.h"
 
-/* Max transfer size done by I2C transfer functions */
-#define MAX_XFER_SIZE  80
-
 /* debug */
 static int dvb_usb_cxusb_debug;
 module_param_named(debug, dvb_usb_cxusb_debug, int, 0644);

@@ -61,23 +58,27 @@ DVB_DEFINE_MOD_OPT_ADAPTER_NR(adapter_nr);
 static int cxusb_ctrl_msg(struct dvb_usb_device *d,
 			  u8 cmd, u8 *wbuf, int wlen, u8 *rbuf, int rlen)
 {
-	int wo = (rbuf == NULL || rlen == 0); /* write-only */
-	u8 sndbuf[MAX_XFER_SIZE];
+	struct cxusb_state *st = d->priv;
+	int ret, wo;
 
-	if (1 + wlen > sizeof(sndbuf)) {
-		warn("i2c wr: len=%d is too big!\n",
-		     wlen);
+	if (1 + wlen > MAX_XFER_SIZE) {
+		warn("i2c wr: len=%d is too big!\n", wlen);
 		return -EOPNOTSUPP;
 	}
 
-	memset(sndbuf, 0, 1+wlen);
+	wo = (rbuf == NULL || rlen == 0); /* write-only */
 
-	sndbuf[0] = cmd;
-	memcpy(&sndbuf[1], wbuf, wlen);
+	mutex_lock(&st->data_mutex);
+	st->data[0] = cmd;
+	memcpy(&st->data[1], wbuf, wlen);
 	if (wo)
-		return dvb_usb_generic_write(d, sndbuf, 1+wlen);
+		ret = dvb_usb_generic_write(d, st->data, 1 + wlen);
 	else
-		return dvb_usb_generic_rw(d, sndbuf, 1+wlen, rbuf, rlen, 0);
+		ret = dvb_usb_generic_rw(d, st->data, 1 + wlen,
+					 rbuf, rlen, 0);
+
+	mutex_unlock(&st->data_mutex);
+	return ret;
 }
 
 /* GPIO */

@@ -1460,36 +1461,43 @@ static struct dvb_usb_device_properties cxusb_mygica_t230_properties;
 static int cxusb_probe(struct usb_interface *intf,
 		       const struct usb_device_id *id)
 {
+	struct dvb_usb_device *d;
+	struct cxusb_state *st;
+
 	if (0 == dvb_usb_device_init(intf, &cxusb_medion_properties,
-				     THIS_MODULE, NULL, adapter_nr) ||
+				     THIS_MODULE, &d, adapter_nr) ||
 	    0 == dvb_usb_device_init(intf, &cxusb_bluebird_lgh064f_properties,
-				     THIS_MODULE, NULL, adapter_nr) ||
+				     THIS_MODULE, &d, adapter_nr) ||
 	    0 == dvb_usb_device_init(intf, &cxusb_bluebird_dee1601_properties,
-				     THIS_MODULE, NULL, adapter_nr) ||
+				     THIS_MODULE, &d, adapter_nr) ||
 	    0 == dvb_usb_device_init(intf, &cxusb_bluebird_lgz201_properties,
-				     THIS_MODULE, NULL, adapter_nr) ||
+				     THIS_MODULE, &d, adapter_nr) ||
 	    0 == dvb_usb_device_init(intf, &cxusb_bluebird_dtt7579_properties,
-				     THIS_MODULE, NULL, adapter_nr) ||
+				     THIS_MODULE, &d, adapter_nr) ||
 	    0 == dvb_usb_device_init(intf, &cxusb_bluebird_dualdig4_properties,
-				     THIS_MODULE, NULL, adapter_nr) ||
+				     THIS_MODULE, &d, adapter_nr) ||
 	    0 == dvb_usb_device_init(intf, &cxusb_bluebird_nano2_properties,
-				     THIS_MODULE, NULL, adapter_nr) ||
+				     THIS_MODULE, &d, adapter_nr) ||
 	    0 == dvb_usb_device_init(intf,
 				&cxusb_bluebird_nano2_needsfirmware_properties,
-				     THIS_MODULE, NULL, adapter_nr) ||
+				     THIS_MODULE, &d, adapter_nr) ||
 	    0 == dvb_usb_device_init(intf, &cxusb_aver_a868r_properties,
-				     THIS_MODULE, NULL, adapter_nr) ||
+				     THIS_MODULE, &d, adapter_nr) ||
 	    0 == dvb_usb_device_init(intf,
 				     &cxusb_bluebird_dualdig4_rev2_properties,
-				     THIS_MODULE, NULL, adapter_nr) ||
+				     THIS_MODULE, &d, adapter_nr) ||
 	    0 == dvb_usb_device_init(intf, &cxusb_d680_dmb_properties,
-				     THIS_MODULE, NULL, adapter_nr) ||
+				     THIS_MODULE, &d, adapter_nr) ||
 	    0 == dvb_usb_device_init(intf, &cxusb_mygica_d689_properties,
-				     THIS_MODULE, NULL, adapter_nr) ||
+				     THIS_MODULE, &d, adapter_nr) ||
 	    0 == dvb_usb_device_init(intf, &cxusb_mygica_t230_properties,
-				     THIS_MODULE, NULL, adapter_nr) ||
-	    0)
+				     THIS_MODULE, &d, adapter_nr) ||
+	    0) {
+		st = d->priv;
+		mutex_init(&st->data_mutex);
+
 		return 0;
+	}
 
 	return -EINVAL;
 }

index 527ff7905e15..9f3ee0e47d5c 100644
@@ -28,10 +28,16 @@
 #define CMD_ANALOG        0x50
 #define CMD_DIGITAL       0x51
 
+/* Max transfer size done by I2C transfer functions */
+#define MAX_XFER_SIZE  80
+
 struct cxusb_state {
 	u8 gpio_write_state[3];
 	struct i2c_client *i2c_client_demod;
 	struct i2c_client *i2c_client_tuner;
+
+	unsigned char data[MAX_XFER_SIZE];
+	struct mutex data_mutex;
 };
 
 #endif

index f3196658fb70..515f89dba199 100644
@@ -292,13 +292,15 @@ static int dib0700_i2c_xfer_legacy(struct i2c_adapter *adap,
 
 			/* special thing in the current firmware: when length is zero the read-failed */
 			len = dib0700_ctrl_rd(d, st->buf, msg[i].len + 2,
-					msg[i+1].buf, msg[i+1].len);
+					      st->buf, msg[i + 1].len);
 			if (len <= 0) {
 				deb_info("I2C read failed on address 0x%02x\n",
 						msg[i].addr);
 				break;
 			}
 
+			memcpy(msg[i + 1].buf, st->buf, msg[i + 1].len);
+
 			msg[i+1].len = len;
 
 			i++;

index 0857b56e652c..ef1b8ee75c57 100644
@@ -508,8 +508,6 @@ static int stk7700ph_tuner_attach(struct dvb_usb_adapter *adap)
 
 #define DEFAULT_RC_INTERVAL 50
 
-static u8 rc_request[] = { REQUEST_POLL_RC, 0 };
-
 /*
  * This function is used only when firmware is < 1.20 version. Newer
  * firmwares use bulk mode, with functions implemented at dib0700_core,

@@ -517,7 +515,6 @@ static u8 rc_request[] = { REQUEST_POLL_RC, 0 };
  */
 static int dib0700_rc_query_old_firmware(struct dvb_usb_device *d)
 {
-	u8 key[4];
 	enum rc_type protocol;
 	u32 scancode;
 	u8 toggle;

@@ -532,39 +529,43 @@ static int dib0700_rc_query_old_firmware(struct dvb_usb_device *d)
 		return 0;
 	}
 
-	i = dib0700_ctrl_rd(d, rc_request, 2, key, 4);
+	st->buf[0] = REQUEST_POLL_RC;
+	st->buf[1] = 0;
+
+	i = dib0700_ctrl_rd(d, st->buf, 2, st->buf, 4);
 	if (i <= 0) {
 		err("RC Query Failed");
-		return -1;
+		return -EIO;
 	}
 
 	/* losing half of KEY_0 events from Philipps rc5 remotes.. */
-	if (key[0] == 0 && key[1] == 0 && key[2] == 0 && key[3] == 0)
+	if (st->buf[0] == 0 && st->buf[1] == 0
+	    && st->buf[2] == 0 && st->buf[3] == 0)
 		return 0;
 
-	/* info("%d: %2X %2X %2X %2X",dvb_usb_dib0700_ir_proto,(int)key[3-2],(int)key[3-3],(int)key[3-1],(int)key[3]);  */
+	/* info("%d: %2X %2X %2X %2X",dvb_usb_dib0700_ir_proto,(int)st->buf[3 - 2],(int)st->buf[3 - 3],(int)st->buf[3 - 1],(int)st->buf[3]);  */
 
 	dib0700_rc_setup(d, NULL); /* reset ir sensor data to prevent false events */
 
 	switch (d->props.rc.core.protocol) {
 	case RC_BIT_NEC:
 		/* NEC protocol sends repeat code as 0 0 0 FF */
-		if ((key[3-2] == 0x00) && (key[3-3] == 0x00) &&
-		    (key[3] == 0xff)) {
+		if ((st->buf[3 - 2] == 0x00) && (st->buf[3 - 3] == 0x00) &&
+		    (st->buf[3] == 0xff)) {
 			rc_repeat(d->rc_dev);
 			return 0;
 		}
 
 		protocol = RC_TYPE_NEC;
-		scancode = RC_SCANCODE_NEC(key[3-2], key[3-3]);
+		scancode = RC_SCANCODE_NEC(st->buf[3 - 2], st->buf[3 - 3]);
 		toggle = 0;
 		break;
 
 	default:
 		/* RC-5 protocol changes toggle bit on new keypress */
 		protocol = RC_TYPE_RC5;
-		scancode = RC_SCANCODE_RC5(key[3-2], key[3-3]);
-		toggle = key[3-1];
+		scancode = RC_SCANCODE_RC5(st->buf[3 - 2], st->buf[3 - 3]);
+		toggle = st->buf[3 - 1];
 		break;
 	}
 

index 515f89dba199..92d5408684ac 100644
@@ -213,7 +213,7 @@ static int dib0700_i2c_xfer_new(struct i2c_adapter *adap, struct i2c_msg *msg,
 						 usb_rcvctrlpipe(d->udev, 0),
 						 REQUEST_NEW_I2C_READ,
 						 USB_TYPE_VENDOR | USB_DIR_IN,
-						 value, index, msg[i].buf,
+						 value, index, st->buf,
 						 msg[i].len,
 						 USB_CTRL_GET_TIMEOUT);
 			if (result < 0) {

@@ -221,6 +221,14 @@ static int dib0700_i2c_xfer_new(struct i2c_adapter *adap, struct i2c_msg *msg,
 				break;
 			}
 
+			if (msg[i].len > sizeof(st->buf)) {
+				deb_info("buffer too small to fit %d bytes\n",
+					 msg[i].len);
+				return -EIO;
+			}
+
+			memcpy(msg[i].buf, st->buf, msg[i].len);
+
 			deb_data("<<< ");
 			debug_dump(msg[i].buf, msg[i].len, deb_data);
 

@@ -238,6 +246,13 @@ static int dib0700_i2c_xfer_new(struct i2c_adapter *adap, struct i2c_msg *msg,
 			/* I2C ctrl + FE bus; */
 			st->buf[3] = ((gen_mode << 6) & 0xC0) |
 				 ((bus_mode << 4) & 0x30);
+
+			if (msg[i].len > sizeof(st->buf) - 4) {
+				deb_info("i2c message to big: %d\n",
+					 msg[i].len);
+				return -EIO;
+			}
+
 			/* The Actual i2c payload */
 			memcpy(&st->buf[4], msg[i].buf, msg[i].len);
 

@@ -283,6 +298,11 @@ static int dib0700_i2c_xfer_legacy(struct i2c_adapter *adap,
 		/* fill in the address */
 		st->buf[1] = msg[i].addr << 1;
 		/* fill the buffer */
+		if (msg[i].len > sizeof(st->buf) - 2) {
+			deb_info("i2c xfer to big: %d\n",
+				msg[i].len);
+			return -EIO;
+		}
 		memcpy(&st->buf[2], msg[i].buf, msg[i].len);
 
 		/* write/read request */

@@ -299,6 +319,11 @@ static int dib0700_i2c_xfer_legacy(struct i2c_adapter *adap,
 				break;
 			}
 
+			if (msg[i + 1].len > sizeof(st->buf)) {
+				deb_info("i2c xfer buffer to small for %d\n",
+					msg[i].len);
+				return -EIO;
+			}
 			memcpy(msg[i + 1].buf, st->buf, msg[i + 1].len);
 
 			msg[i+1].len = len;

index 4b08c2a47ae2..951f3dac9082 100644
@@ -63,72 +63,117 @@ EXPORT_SYMBOL(dibusb_pid_filter_ctrl);
 
 int dibusb_power_ctrl(struct dvb_usb_device *d, int onoff)
 {
-	u8 b[3];
+	u8 *b;
 	int ret;
+
+	b = kmalloc(3, GFP_KERNEL);
+	if (!b)
+		return -ENOMEM;
+
 	b[0] = DIBUSB_REQ_SET_IOCTL;
 	b[1] = DIBUSB_IOCTL_CMD_POWER_MODE;
 	b[2] = onoff ? DIBUSB_IOCTL_POWER_WAKEUP : DIBUSB_IOCTL_POWER_SLEEP;
-	ret = dvb_usb_generic_write(d,b,3);
+
+	ret = dvb_usb_generic_write(d, b, 3);
+
+	kfree(b);
+
 	msleep(10);
+
 	return ret;
 }
 EXPORT_SYMBOL(dibusb_power_ctrl);
 
 int dibusb2_0_streaming_ctrl(struct dvb_usb_adapter *adap, int onoff)
 {
-	u8 b[3] = { 0 };
 	int ret;
+	u8 *b;
+
+	b = kmalloc(3, GFP_KERNEL);
+	if (!b)
+		return -ENOMEM;
 
 	if ((ret = dibusb_streaming_ctrl(adap,onoff)) < 0)
-		return ret;
+		goto ret;
 
 	if (onoff) {
 		b[0] = DIBUSB_REQ_SET_STREAMING_MODE;
 		b[1] = 0x00;
-		if ((ret = dvb_usb_generic_write(adap->dev,b,2)) < 0)
-			return ret;
+		ret = dvb_usb_generic_write(adap->dev, b, 2);
+		if (ret  < 0)
+			goto ret;
 	}
 
 	b[0] = DIBUSB_REQ_SET_IOCTL;
 	b[1] = onoff ? DIBUSB_IOCTL_CMD_ENABLE_STREAM : DIBUSB_IOCTL_CMD_DISABLE_STREAM;
-	return dvb_usb_generic_write(adap->dev,b,3);
+	ret = dvb_usb_generic_write(adap->dev, b, 3);
+
+ret:
+	kfree(b);
+	return ret;
 }
 EXPORT_SYMBOL(dibusb2_0_streaming_ctrl);
 
 int dibusb2_0_power_ctrl(struct dvb_usb_device *d, int onoff)
 {
-	if (onoff) {
-		u8 b[3] = { DIBUSB_REQ_SET_IOCTL, DIBUSB_IOCTL_CMD_POWER_MODE, DIBUSB_IOCTL_POWER_WAKEUP };
-		return dvb_usb_generic_write(d,b,3);
-	} else
+	u8 *b;
+	int ret;
+
+	if (!onoff)
 		return 0;
+
+	b = kmalloc(3, GFP_KERNEL);
+	if (!b)
+		return -ENOMEM;
+
+	b[0] = DIBUSB_REQ_SET_IOCTL;
+	b[1] = DIBUSB_IOCTL_CMD_POWER_MODE;
+	b[2] = DIBUSB_IOCTL_POWER_WAKEUP;
+
+	ret = dvb_usb_generic_write(d, b, 3);
+
+	kfree(b);
+
+	return ret;
 }
 EXPORT_SYMBOL(dibusb2_0_power_ctrl);
 
 static int dibusb_i2c_msg(struct dvb_usb_device *d, u8 addr,
 			  u8 *wbuf, u16 wlen, u8 *rbuf, u16 rlen)
 {
-	u8 sndbuf[MAX_XFER_SIZE]; /* lead(1) devaddr,direction(1) addr(2) data(wlen) (len(2) (when reading)) */
+	u8 *sndbuf;
+	int ret, wo, len;
+
 	/* write only ? */
-	int wo = (rbuf == NULL || rlen == 0),
-		len = 2 + wlen + (wo ? 0 : 2);
+	wo = (rbuf == NULL || rlen == 0);
 
-	if (4 + wlen > sizeof(sndbuf)) {
+	len = 2 + wlen + (wo ? 0 : 2);
+
+	sndbuf = kmalloc(MAX_XFER_SIZE, GFP_KERNEL);
+	if (!sndbuf)
+		return -ENOMEM;
+
+	if (4 + wlen > MAX_XFER_SIZE) {
 		warn("i2c wr: len=%d is too big!\n", wlen);
-		return -EOPNOTSUPP;
+		ret = -EOPNOTSUPP;
+		goto ret;
 	}
 
 	sndbuf[0] = wo ? DIBUSB_REQ_I2C_WRITE : DIBUSB_REQ_I2C_READ;
 	sndbuf[1] = (addr << 1) | (wo ? 0 : 1);
 
-	memcpy(&sndbuf[2],wbuf,wlen);
+	memcpy(&sndbuf[2], wbuf, wlen);
 
 	if (!wo) {
-		sndbuf[wlen+2] = (rlen >> 8) & 0xff;
-		sndbuf[wlen+3] = rlen & 0xff;
+		sndbuf[wlen + 2] = (rlen >> 8) & 0xff;
+		sndbuf[wlen + 3] = rlen & 0xff;
 	}
 
-	return dvb_usb_generic_rw(d,sndbuf,len,rbuf,rlen,0);
+	ret = dvb_usb_generic_rw(d, sndbuf, len, rbuf, rlen, 0);
+
+ret:
+	kfree(sndbuf);
+	return ret;
 }
 
 /*

@@ -320,11 +365,23 @@ EXPORT_SYMBOL(rc_map_dibusb_table);
 
 int dibusb_rc_query(struct dvb_usb_device *d, u32 *event, int *state)
 {
-	u8 key[5],cmd = DIBUSB_REQ_POLL_REMOTE;
-	dvb_usb_generic_rw(d,&cmd,1,key,5,0);
-	dvb_usb_nec_rc_key_to_event(d,key,event,state);
-	if (key[0] != 0)
-		deb_info("key: %*ph\n", 5, key);
+	u8 *buf;
+
+	buf = kmalloc(5, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	buf[0] = DIBUSB_REQ_POLL_REMOTE;
+
+	dvb_usb_generic_rw(d, buf, 1, buf, 5, 0);
+
+	dvb_usb_nec_rc_key_to_event(d, buf, event, state);
+
+	if (buf[0] != 0)
+		deb_info("key: %*ph\n", 5, buf);
+
+	kfree(buf);
+
 	return 0;
 }
 EXPORT_SYMBOL(dibusb_rc_query);

index 3f82163d8ab8..697be2a17ade 100644
@@ -96,6 +96,9 @@
 #define DIBUSB_IOCTL_CMD_ENABLE_STREAM	0x01
 #define DIBUSB_IOCTL_CMD_DISABLE_STREAM	0x02
 
+/* Max transfer size done by I2C transfer functions */
+#define MAX_XFER_SIZE  64
+
 struct dibusb_state {
 	struct dib_fe_xfer_ops ops;
 	int mt2060_present;

index 951f3dac9082..b0fd9a609352 100644
@@ -366,6 +366,7 @@ EXPORT_SYMBOL(rc_map_dibusb_table);
 int dibusb_rc_query(struct dvb_usb_device *d, u32 *event, int *state)
 {
 	u8 *buf;
+	int ret;
 
 	buf = kmalloc(5, GFP_KERNEL);
 	if (!buf)

@@ -373,7 +374,9 @@ int dibusb_rc_query(struct dvb_usb_device *d, u32 *event, int *state)
 
 	buf[0] = DIBUSB_REQ_POLL_REMOTE;
 
-	dvb_usb_generic_rw(d, buf, 1, buf, 5, 0);
+	ret = dvb_usb_generic_rw(d, buf, 1, buf, 5, 0);
+	if (ret < 0)
+		goto ret;
 
 	dvb_usb_nec_rc_key_to_event(d, buf, event, state);
 

@@ -382,6 +385,7 @@ int dibusb_rc_query(struct dvb_usb_device *d, u32 *event, int *state)
 
 	kfree(buf);
 
-	return 0;
+ret:
+	return ret;
 }
 EXPORT_SYMBOL(dibusb_rc_query);

index 63134335c994..09f8c28bd4db 100644
@@ -28,20 +28,22 @@ DVB_DEFINE_MOD_OPT_ADAPTER_NR(adapter_nr);
 static int digitv_ctrl_msg(struct dvb_usb_device *d,
 		u8 cmd, u8 vv, u8 *wbuf, int wlen, u8 *rbuf, int rlen)
 {
+	struct digitv_state *st = d->priv;
 	int wo = (rbuf == NULL || rlen == 0); /* write-only */
-	u8 sndbuf[7],rcvbuf[7];
-	memset(sndbuf,0,7); memset(rcvbuf,0,7);
 
-	sndbuf[0] = cmd;
-	sndbuf[1] = vv;
-	sndbuf[2] = wo ? wlen : rlen;
+	memset(st->sndbuf, 0, 7);
+	memset(st->rcvbuf, 0, 7);
+
+	st->sndbuf[0] = cmd;
+	st->sndbuf[1] = vv;
+	st->sndbuf[2] = wo ? wlen : rlen;
 
 	if (wo) {
-		memcpy(&sndbuf[3],wbuf,wlen);
-		dvb_usb_generic_write(d,sndbuf,7);
+		memcpy(&st->sndbuf[3], wbuf, wlen);
+		dvb_usb_generic_write(d, st->sndbuf, 7);
 	} else {
-		dvb_usb_generic_rw(d,sndbuf,7,rcvbuf,7,10);
-		memcpy(rbuf,&rcvbuf[3],rlen);
+		dvb_usb_generic_rw(d, st->sndbuf, 7, st->rcvbuf, 7, 10);
+		memcpy(rbuf, &st->rcvbuf[3], rlen);
 	}
 	return 0;
 }

index 908c09f4966b..cf104689bdff 100644
@@ -6,6 +6,9 @@
 
 struct digitv_state {
     int is_nxt6000;
+
+    unsigned char sndbuf[7];
+    unsigned char rcvbuf[7];
 };
 
 /* protocol (from usblogging and the SDK:

index c09332bd99cb..9bb15f7b48db 100644
@@ -105,8 +105,6 @@ static int dtt200u_fe_set_frontend(struct dvb_frontend *fe)
 {
 	struct dtv_frontend_properties *fep = &fe->dtv_property_cache;
 	struct dtt200u_fe_state *state = fe->demodulator_priv;
-	int i;
-	enum fe_status st;
 	u16 freq = fep->frequency / 250000;
 	u8 bwbuf[2] = { SET_BANDWIDTH, 0 },freqbuf[3] = { SET_RF_FREQ, 0, 0 };
 

@@ -130,13 +128,6 @@ static int dtt200u_fe_set_frontend(struct dvb_frontend *fe)
 	freqbuf[2] = (freq >> 8) & 0xff;
 	dvb_usb_generic_write(state->d,freqbuf,3);
 
-	for (i = 0; i < 30; i++) {
-		msleep(20);
-		dtt200u_fe_read_status(fe, &st);
-		if (st & FE_TIMEDOUT)
-			continue;
-	}
-
 	return 0;
 }
 

index 9bb15f7b48db..7f7f64be6353 100644
@@ -18,17 +18,22 @@ struct dtt200u_fe_state {
 
 	struct dtv_frontend_properties fep;
 	struct dvb_frontend frontend;
+
+	unsigned char data[80];
+	struct mutex data_mutex;
 };
 
 static int dtt200u_fe_read_status(struct dvb_frontend *fe,
 				  enum fe_status *stat)
 {
 	struct dtt200u_fe_state *state = fe->demodulator_priv;
-	u8 st = GET_TUNE_STATUS, b[3];
 
-	dvb_usb_generic_rw(state->d,&st,1,b,3,0);
+	mutex_lock(&state->data_mutex);
+	state->data[0] = GET_TUNE_STATUS;
 
-	switch (b[0]) {
+	dvb_usb_generic_rw(state->d, state->data, 1, state->data, 3, 0);
+
+	switch (state->data[0]) {
 		case 0x01:
 			*stat = FE_HAS_SIGNAL | FE_HAS_CARRIER |
 				FE_HAS_VITERBI | FE_HAS_SYNC | FE_HAS_LOCK;

@@ -41,51 +46,75 @@ static int dtt200u_fe_read_status(struct dvb_frontend *fe,
 			*stat = 0;
 			break;
 	}
+	mutex_unlock(&state->data_mutex);
 	return 0;
 }
 
 static int dtt200u_fe_read_ber(struct dvb_frontend* fe, u32 *ber)
 {
 	struct dtt200u_fe_state *state = fe->demodulator_priv;
-	u8 bw = GET_VIT_ERR_CNT,b[3];
-	dvb_usb_generic_rw(state->d,&bw,1,b,3,0);
-	*ber = (b[0] << 16) | (b[1] << 8) | b[2];
+
+	mutex_lock(&state->data_mutex);
+	state->data[0] = GET_VIT_ERR_CNT;
+
+	dvb_usb_generic_rw(state->d, state->data, 1, state->data, 3, 0);
+	*ber = (state->data[0] << 16) | (state->data[1] << 8) | state->data[2];
+
+	mutex_unlock(&state->data_mutex);
 	return 0;
 }
 
 static int dtt200u_fe_read_unc_blocks(struct dvb_frontend* fe, u32 *unc)
 {
 	struct dtt200u_fe_state *state = fe->demodulator_priv;
-	u8 bw = GET_RS_UNCOR_BLK_CNT,b[2];
 
-	dvb_usb_generic_rw(state->d,&bw,1,b,2,0);
-	*unc = (b[0] << 8) | b[1];
-	return 0;
+	mutex_lock(&state->data_mutex);
+	state->data[0] = GET_RS_UNCOR_BLK_CNT;
+
+	dvb_usb_generic_rw(state->d, state->data, 1, state->data, 2, 0);
+
+	mutex_unlock(&state->data_mutex);
+	return ret;
 }
 
 static int dtt200u_fe_read_signal_strength(struct dvb_frontend* fe, u16 *strength)
 {
 	struct dtt200u_fe_state *state = fe->demodulator_priv;
-	u8 bw = GET_AGC, b;
-	dvb_usb_generic_rw(state->d,&bw,1,&b,1,0);
-	*strength = (b << 8) | b;
-	return 0;
+
+	mutex_lock(&state->data_mutex);
+	state->data[0] = GET_AGC;
+
+	dvb_usb_generic_rw(state->d, state->data, 1, state->data, 1, 0);
+
+	mutex_unlock(&state->data_mutex);
+	return ret;
 }
 
 static int dtt200u_fe_read_snr(struct dvb_frontend* fe, u16 *snr)
 {
 	struct dtt200u_fe_state *state = fe->demodulator_priv;
-	u8 bw = GET_SNR,br;
-	dvb_usb_generic_rw(state->d,&bw,1,&br,1,0);
-	*snr = ~((br << 8) | br);
-	return 0;
+
+	mutex_lock(&state->data_mutex);
+	state->data[0] = GET_SNR;
+
+	dvb_usb_generic_rw(state->d, state->data, 1, state->data, 1, 0);
+
+	mutex_unlock(&state->data_mutex);
+	return ret;
 }
 
 static int dtt200u_fe_init(struct dvb_frontend* fe)
 {
 	struct dtt200u_fe_state *state = fe->demodulator_priv;
-	u8 b = SET_INIT;
-	return dvb_usb_generic_write(state->d,&b,1);
+	int ret;
+
+	mutex_lock(&state->data_mutex);
+	state->data[0] = SET_INIT;
+
+	ret = dvb_usb_generic_write(state->d, state->data, 1);
+	mutex_unlock(&state->data_mutex);
+
+	return ret;
 }
 
 static int dtt200u_fe_sleep(struct dvb_frontend* fe)

@@ -106,29 +135,34 @@ static int dtt200u_fe_set_frontend(struct dvb_frontend *fe)
 	struct dtv_frontend_properties *fep = &fe->dtv_property_cache;
 	struct dtt200u_fe_state *state = fe->demodulator_priv;
 	u16 freq = fep->frequency / 250000;
-	u8 bwbuf[2] = { SET_BANDWIDTH, 0 },freqbuf[3] = { SET_RF_FREQ, 0, 0 };
 
+	mutex_lock(&state->data_mutex);
+	state->data[0] = SET_BANDWIDTH;
 	switch (fep->bandwidth_hz) {
 	case 8000000:
-		bwbuf[1] = 8;
+		state->data[1] = 8;
 		break;
 	case 7000000:
-		bwbuf[1] = 7;
+		state->data[1] = 7;
 		break;
 	case 6000000:
-		bwbuf[1] = 6;
+		state->data[1] = 6;
 		break;
 	default:
-		return -EINVAL;
+		ret = -EINVAL;
+		goto ret;
 	}
 
-	dvb_usb_generic_write(state->d,bwbuf,2);
+	dvb_usb_generic_write(state->d, state->data, 2);
 
-	freqbuf[1] = freq & 0xff;
-	freqbuf[2] = (freq >> 8) & 0xff;
-	dvb_usb_generic_write(state->d,freqbuf,3);
+	state->data[0] = SET_RF_FREQ;
+	state->data[1] = freq & 0xff;
+	state->data[2] = (freq >> 8) & 0xff;
+	dvb_usb_generic_write(state->d, state->data, 3);
 
-	return 0;
+ret:
+	mutex_unlock(&state->data_mutex);
+	return ret;
 }
 
 static int dtt200u_fe_get_frontend(struct dvb_frontend* fe,

@@ -160,6 +194,7 @@ struct dvb_frontend* dtt200u_fe_attach(struct dvb_usb_device *d)
 	deb_info("attaching frontend dtt200u\n");
 
 	state->d = d;
+	mutex_init(&state->data_mutex);
 
 	memcpy(&state->frontend.ops,&dtt200u_fe_ops,sizeof(struct dvb_frontend_ops));
 	state->frontend.demodulator_priv = state;

index 7f7f64be6353..f5c042baa254 100644
@@ -27,11 +27,17 @@ static int dtt200u_fe_read_status(struct dvb_frontend *fe,
 				  enum fe_status *stat)
 {
 	struct dtt200u_fe_state *state = fe->demodulator_priv;
+	int ret;
 
 	mutex_lock(&state->data_mutex);
 	state->data[0] = GET_TUNE_STATUS;
 
-	dvb_usb_generic_rw(state->d, state->data, 1, state->data, 3, 0);
+	ret = dvb_usb_generic_rw(state->d, state->data, 1, state->data, 3, 0);
+	if (ret < 0) {
+		*stat = 0;
+		mutex_unlock(&state->data_mutex);
+		return ret;
+	}
 
 	switch (state->data[0]) {
 		case 0x01:

@@ -53,25 +59,30 @@ static int dtt200u_fe_read_status(struct dvb_frontend *fe,
 static int dtt200u_fe_read_ber(struct dvb_frontend* fe, u32 *ber)
 {
 	struct dtt200u_fe_state *state = fe->demodulator_priv;
+	int ret;
 
 	mutex_lock(&state->data_mutex);
 	state->data[0] = GET_VIT_ERR_CNT;
 
-	dvb_usb_generic_rw(state->d, state->data, 1, state->data, 3, 0);
-	*ber = (state->data[0] << 16) | (state->data[1] << 8) | state->data[2];
+	ret = dvb_usb_generic_rw(state->d, state->data, 1, state->data, 3, 0);
+	if (ret >= 0)
+		*ber = (state->data[0] << 16) | (state->data[1] << 8) | state->data[2];
 
 	mutex_unlock(&state->data_mutex);
-	return 0;
+	return ret;
 }
 
 static int dtt200u_fe_read_unc_blocks(struct dvb_frontend* fe, u32 *unc)
 {
 	struct dtt200u_fe_state *state = fe->demodulator_priv;
+	int ret;
 
 	mutex_lock(&state->data_mutex);
 	state->data[0] = GET_RS_UNCOR_BLK_CNT;
 
-	dvb_usb_generic_rw(state->d, state->data, 1, state->data, 2, 0);
+	ret = dvb_usb_generic_rw(state->d, state->data, 1, state->data, 2, 0);
+	if (ret >= 0)
+		*unc = (state->data[0] << 8) | state->data[1];
 
 	mutex_unlock(&state->data_mutex);
 	return ret;

@@ -80,11 +91,14 @@ static int dtt200u_fe_read_unc_blocks(struct dvb_frontend* fe, u32 *unc)
 static int dtt200u_fe_read_signal_strength(struct dvb_frontend* fe, u16 *strength)
 {
 	struct dtt200u_fe_state *state = fe->demodulator_priv;
+	int ret;
 
 	mutex_lock(&state->data_mutex);
 	state->data[0] = GET_AGC;
 
-	dvb_usb_generic_rw(state->d, state->data, 1, state->data, 1, 0);
+	ret = dvb_usb_generic_rw(state->d, state->data, 1, state->data, 1, 0);
+	if (ret >= 0)
+		*strength = (state->data[0] << 8) | state->data[0];
 
 	mutex_unlock(&state->data_mutex);
 	return ret;

@@ -93,11 +107,14 @@ static int dtt200u_fe_read_signal_strength(struct dvb_frontend* fe, u16 *strengt
 static int dtt200u_fe_read_snr(struct dvb_frontend* fe, u16 *snr)
 {
 	struct dtt200u_fe_state *state = fe->demodulator_priv;
+	int ret;
 
 	mutex_lock(&state->data_mutex);
 	state->data[0] = GET_SNR;
 
-	dvb_usb_generic_rw(state->d, state->data, 1, state->data, 1, 0);
+	ret = dvb_usb_generic_rw(state->d, state->data, 1, state->data, 1, 0);
+	if (ret >= 0)
+		*snr = ~((state->data[0] << 8) | state->data[0]);
 
 	mutex_unlock(&state->data_mutex);
 	return ret;

@@ -134,6 +151,7 @@ static int dtt200u_fe_set_frontend(struct dvb_frontend *fe)
 {
 	struct dtv_frontend_properties *fep = &fe->dtv_property_cache;
 	struct dtt200u_fe_state *state = fe->demodulator_priv;
+	int ret;
 	u16 freq = fep->frequency / 250000;
 
 	mutex_lock(&state->data_mutex);

@@ -153,12 +171,16 @@ static int dtt200u_fe_set_frontend(struct dvb_frontend *fe)
 		goto ret;
 	}
 
-	dvb_usb_generic_write(state->d, state->data, 2);
+	ret = dvb_usb_generic_write(state->d, state->data, 2);
+	if (ret < 0)
+		goto ret;
 
 	state->data[0] = SET_RF_FREQ;
 	state->data[1] = freq & 0xff;
 	state->data[2] = (freq >> 8) & 0xff;
-	dvb_usb_generic_write(state->d, state->data, 3);
+	ret = dvb_usb_generic_write(state->d, state->data, 3);
+	if (ret < 0)
+		goto ret;
 
 ret:
 	mutex_unlock(&state->data_mutex);

index d2a01b50af0d..7706938b5167 100644
@@ -20,74 +20,103 @@ MODULE_PARM_DESC(debug, "set debugging level (1=info,xfer=2 (or-able))." DVB_USB
 
 DVB_DEFINE_MOD_OPT_ADAPTER_NR(adapter_nr);
 
+struct dtt200u_state {
+	unsigned char data[80];
+	struct mutex data_mutex;
+};
+
 static int dtt200u_power_ctrl(struct dvb_usb_device *d, int onoff)
 {
-	u8 b = SET_INIT;
+	struct dtt200u_state *st = d->priv;
+
+	mutex_lock(&st->data_mutex);
+
+	st->data[0] = SET_INIT;
 
 	if (onoff)
-		dvb_usb_generic_write(d,&b,2);
+		dvb_usb_generic_write(d, st->data, 2);
 
+	mutex_unlock(&st->data_mutex);
 	return 0;
 }
 
 static int dtt200u_streaming_ctrl(struct dvb_usb_adapter *adap, int onoff)
 {
-	u8 b_streaming[2] = { SET_STREAMING, onoff };
-	u8 b_rst_pid = RESET_PID_FILTER;
+	struct dtt200u_state *st = adap->dev->priv;
 
-	dvb_usb_generic_write(adap->dev, b_streaming, 2);
+	mutex_lock(&st->data_mutex);
+	st->data[0] = SET_STREAMING;
+	st->data[1] = onoff;
+
+	dvb_usb_generic_write(adap->dev, st->data, 2);
+
+	if (onoff)
+		return 0;
+
+	st->data[0] = RESET_PID_FILTER;
+	dvb_usb_generic_write(adap->dev, st->data, 1);
+
+	mutex_unlock(&st->data_mutex);
 
-	if (onoff == 0)
-		dvb_usb_generic_write(adap->dev, &b_rst_pid, 1);
 	return 0;
 }
 
 static int dtt200u_pid_filter(struct dvb_usb_adapter *adap, int index, u16 pid, int onoff)
 {
-	u8 b_pid[4];
+	struct dtt200u_state *st = adap->dev->priv;
+	int ret;
+
 	pid = onoff ? pid : 0;
 
-	b_pid[0] = SET_PID_FILTER;
-	b_pid[1] = index;
-	b_pid[2] = pid & 0xff;
-	b_pid[3] = (pid >> 8) & 0x1f;
+	mutex_lock(&st->data_mutex);
+	st->data[0] = SET_PID_FILTER;
+	st->data[1] = index;
+	st->data[2] = pid & 0xff;
+	st->data[3] = (pid >> 8) & 0x1f;
 
-	return dvb_usb_generic_write(adap->dev, b_pid, 4);
+	ret = dvb_usb_generic_write(adap->dev, st->data, 4);
+	mutex_unlock(&st->data_mutex);
+
+	return ret;
 }
 
 static int dtt200u_rc_query(struct dvb_usb_device *d)
 {
-	u8 key[5],cmd = GET_RC_CODE;
+	struct dtt200u_state *st = d->priv;
 	u32 scancode;
 
-	dvb_usb_generic_rw(d,&cmd,1,key,5,0);
-	if (key[0] == 1) {
+	mutex_lock(&st->data_mutex);
+	st->data[0] = GET_RC_CODE;
+
+	dvb_usb_generic_rw(d, st->data, 1, st->data, 5, 0);
+	if (st->data[0] == 1) {
 		enum rc_type proto = RC_TYPE_NEC;
 
-		scancode = key[1];
-		if ((u8) ~key[1] != key[2]) {
+		scancode = st->data[1];
+		if ((u8) ~st->data[1] != st->data[2]) {
 			/* Extended NEC */
 			scancode = scancode << 8;
-			scancode |= key[2];
+			scancode |= st->data[2];
 			proto = RC_TYPE_NECX;
 		}
 		scancode = scancode << 8;
-		scancode |= key[3];
+		scancode |= st->data[3];
 
 		/* Check command checksum is ok */
-		if ((u8) ~key[3] == key[4])
+		if ((u8) ~st->data[3] == st->data[4])
 			rc_keydown(d->rc_dev, proto, scancode, 0);
 		else
 			rc_keyup(d->rc_dev);
-	} else if (key[0] == 2) {
+	} else if (st->data[0] == 2) {
 		rc_repeat(d->rc_dev);
 	} else {
 		rc_keyup(d->rc_dev);
 	}
 
-	if (key[0] != 0)
-		deb_info("key: %*ph\n", 5, key);
+	if (st->data[0] != 0)
+		deb_info("st->data: %*ph\n", 5, st->data);
 
+	mutex_unlock(&st->data_mutex);
 	return 0;
 }
 

@@ -106,17 +135,24 @@ static struct dvb_usb_device_properties wt220u_miglia_properties;
 static int dtt200u_usb_probe(struct usb_interface *intf,
 		const struct usb_device_id *id)
 {
+	struct dvb_usb_device *d;
+	struct dtt200u_state *st;
+
 	if (0 == dvb_usb_device_init(intf, &dtt200u_properties,
-				     THIS_MODULE, NULL, adapter_nr) ||
+				     THIS_MODULE, &d, adapter_nr) ||
 	    0 == dvb_usb_device_init(intf, &wt220u_properties,
-				     THIS_MODULE, NULL, adapter_nr) ||
+				     THIS_MODULE, &d, adapter_nr) ||
 	    0 == dvb_usb_device_init(intf, &wt220u_fc_properties,
-				     THIS_MODULE, NULL, adapter_nr) ||
+				     THIS_MODULE, &d, adapter_nr) ||
 	    0 == dvb_usb_device_init(intf, &wt220u_zl0353_properties,
-				     THIS_MODULE, NULL, adapter_nr) ||
+				     THIS_MODULE, &d, adapter_nr) ||
 	    0 == dvb_usb_device_init(intf, &wt220u_miglia_properties,
-				     THIS_MODULE, NULL, adapter_nr))
+				     THIS_MODULE, &d, adapter_nr)) {
+		st = d->priv;
+		mutex_init(&st->data_mutex);
+
 		return 0;
+	}
 
 	return -ENODEV;
 }

@@ -140,6 +176,8 @@ static struct dvb_usb_device_properties dtt200u_properties = {
 	.usb_ctrl = CYPRESS_FX2,
 	.firmware = "dvb-usb-dtt200u-01.fw",
 
+	.size_of_priv     = sizeof(struct dtt200u_state),
+
 	.num_adapters = 1,
 	.adapter = {
 		{

@@ -190,6 +228,8 @@ static struct dvb_usb_device_properties wt220u_properties = {
 	.usb_ctrl = CYPRESS_FX2,
 	.firmware = "dvb-usb-wt220u-02.fw",
 
+	.size_of_priv     = sizeof(struct dtt200u_state),
+
 	.num_adapters = 1,
 	.adapter = {
 		{

@@ -240,6 +280,8 @@ static struct dvb_usb_device_properties wt220u_fc_properties = {
 	.usb_ctrl = CYPRESS_FX2,
 	.firmware = "dvb-usb-wt220u-fc03.fw",
 
+	.size_of_priv     = sizeof(struct dtt200u_state),
+
 	.num_adapters = 1,
 	.adapter = {
 		{

@@ -290,6 +332,8 @@ static struct dvb_usb_device_properties wt220u_zl0353_properties = {
 	.usb_ctrl = CYPRESS_FX2,
 	.firmware = "dvb-usb-wt220u-zl0353-01.fw",
 
+	.size_of_priv     = sizeof(struct dtt200u_state),
+
 	.num_adapters = 1,
 	.adapter = {
 		{

@@ -340,6 +384,8 @@ static struct dvb_usb_device_properties wt220u_miglia_properties = {
 	.usb_ctrl = CYPRESS_FX2,
 	.firmware = "dvb-usb-wt220u-miglia-01.fw",
 
+	.size_of_priv     = sizeof(struct dtt200u_state),
+
 	.num_adapters = 1,
 	.generic_bulk_ctrl_endpoint = 0x01,
 

index 7706938b5167..f88572c7ae7c 100644
@@ -28,37 +28,42 @@ struct dtt200u_state {
 static int dtt200u_power_ctrl(struct dvb_usb_device *d, int onoff)
 {
 	struct dtt200u_state *st = d->priv;
+	int ret = 0;
 
 	mutex_lock(&st->data_mutex);
 
 	st->data[0] = SET_INIT;
 
 	if (onoff)
-		dvb_usb_generic_write(d, st->data, 2);
+		ret = dvb_usb_generic_write(d, st->data, 2);
 
 	mutex_unlock(&st->data_mutex);
-	return 0;
+	return ret;
 }
 
 static int dtt200u_streaming_ctrl(struct dvb_usb_adapter *adap, int onoff)
 {
 	struct dtt200u_state *st = adap->dev->priv;
+	int ret;
 
 	mutex_lock(&st->data_mutex);
 	st->data[0] = SET_STREAMING;
 	st->data[1] = onoff;
 
-	dvb_usb_generic_write(adap->dev, st->data, 2);
+	ret = dvb_usb_generic_write(adap->dev, st->data, 2);
+	if (ret < 0)
+		goto ret;
 
 	if (onoff)
-		return 0;
+		goto ret;
 
 	st->data[0] = RESET_PID_FILTER;
-	dvb_usb_generic_write(adap->dev, st->data, 1);
+	ret = dvb_usb_generic_write(adap->dev, st->data, 1);
 
+ret:
 	mutex_unlock(&st->data_mutex);
 
-	return 0;
+	return ret;
 }
 
 static int dtt200u_pid_filter(struct dvb_usb_adapter *adap, int index, u16 pid, int onoff)

@@ -84,11 +89,15 @@ static int dtt200u_rc_query(struct dvb_usb_device *d)
 {
 	struct dtt200u_state *st = d->priv;
 	u32 scancode;
+	int ret;
 
 	mutex_lock(&st->data_mutex);
 	st->data[0] = GET_RC_CODE;
 
-	dvb_usb_generic_rw(d, st->data, 1, st->data, 5, 0);
+	ret = dvb_usb_generic_rw(d, st->data, 1, st->data, 5, 0);
+	if (ret < 0)
+		goto ret;
+
 	if (st->data[0] == 1) {
 		enum rc_type proto = RC_TYPE_NEC;
 

@@ -116,8 +125,9 @@ static int dtt200u_rc_query(struct dvb_usb_device *d)
 	if (st->data[0] != 0)
 		deb_info("st->data: %*ph\n", 5, st->data);
 
+ret:
 	mutex_unlock(&st->data_mutex);
-	return 0;
+	return ret;
 }
 
 static int dtt200u_frontend_attach(struct dvb_usb_adapter *adap)

index 3d11df41cac0..c60fb54f445f 100644
@@ -31,9 +31,14 @@ module_param_named(debug, dvb_usb_dtv5100_debug, int, 0644);
 MODULE_PARM_DESC(debug, "set debugging level" DVB_USB_DEBUG_STATUS);
 DVB_DEFINE_MOD_OPT_ADAPTER_NR(adapter_nr);
 
+struct dtv5100_state {
+	unsigned char data[80];
+};
+
 static int dtv5100_i2c_msg(struct dvb_usb_device *d, u8 addr,
 			   u8 *wbuf, u16 wlen, u8 *rbuf, u16 rlen)
 {
+	struct dtv5100_state *st = d->priv;
 	u8 request;
 	u8 type;
 	u16 value;

@@ -60,9 +65,10 @@ static int dtv5100_i2c_msg(struct dvb_usb_device *d, u8 addr,
 	}
 	index = (addr << 8) + wbuf[0];
 
+	memcpy(st->data, rbuf, rlen);
 	msleep(1); /* avoid I2C errors */
 	return usb_control_msg(d->udev, usb_rcvctrlpipe(d->udev, 0), request,
-			       type, value, index, rbuf, rlen,
+			       type, value, index, st->data, rlen,
 			       DTV5100_USB_TIMEOUT);
 }
 

@@ -176,7 +182,7 @@ static struct dvb_usb_device_properties dtv5100_properties = {
 	.caps = DVB_USB_IS_AN_I2C_ADAPTER,
 	.usb_ctrl = DEVICE_SPECIFIC,
 
-	.size_of_priv = 0,
+	.size_of_priv = sizeof(struct dtv5100_state),
 
 	.num_adapters = 1,
 	.adapter = {{

index 5d0384dd45b5..fa215ad37f7b 100644
@@ -24,6 +24,10 @@ MODULE_PARM_DESC(debug, "set debugging level (1=info,xfer=2,rc=4 (or-able))." DV
 
 DVB_DEFINE_MOD_OPT_ADAPTER_NR(adapter_nr);
 
+struct gp8psk_state {
+	unsigned char data[80];
+};
+
 static int gp8psk_get_fw_version(struct dvb_usb_device *d, u8 *fw_vers)
 {
 	return (gp8psk_usb_in_op(d, GET_FW_VERS, 0, 0, fw_vers, 6));

@@ -53,17 +57,19 @@ static void gp8psk_info(struct dvb_usb_device *d)
 
 int gp8psk_usb_in_op(struct dvb_usb_device *d, u8 req, u16 value, u16 index, u8 *b, int blen)
 {
+	struct gp8psk_state *st = d->priv;
 	int ret = 0,try = 0;
 
 	if ((ret = mutex_lock_interruptible(&d->usb_mutex)))
 		return ret;
 
 	while (ret >= 0 && ret != blen && try < 3) {
+		memcpy(st->data, b, blen);
 		ret = usb_control_msg(d->udev,
 			usb_rcvctrlpipe(d->udev,0),
 			req,
 			USB_TYPE_VENDOR | USB_DIR_IN,
-			value,index,b,blen,
+			value, index, st->data, blen,
 			2000);
 		deb_info("reading number %d (ret: %d)\n",try,ret);
 		try++;

@@ -86,6 +92,7 @@ int gp8psk_usb_in_op(struct dvb_usb_device *d, u8 req, u16 value, u16 index, u8
 int gp8psk_usb_out_op(struct dvb_usb_device *d, u8 req, u16 value,
 			     u16 index, u8 *b, int blen)
 {
+	struct gp8psk_state *st = d->priv;
 	int ret;
 
 	deb_xfer("out: req. %x, val: %x, ind: %x, buffer: ",req,value,index);

@@ -94,11 +101,12 @@ int gp8psk_usb_out_op(struct dvb_usb_device *d, u8 req, u16 value,
 	if ((ret = mutex_lock_interruptible(&d->usb_mutex)))
 		return ret;
 
+	memcpy(st->data, b, blen);
 	if (usb_control_msg(d->udev,
 			usb_sndctrlpipe(d->udev,0),
 			req,
 			USB_TYPE_VENDOR | USB_DIR_OUT,
-			value,index,b,blen,
+			value,index, st->data, blen,
 			2000) != blen) {
 		warn("usb out operation failed.");
 		ret = -EIO;

@@ -265,6 +273,8 @@ static struct dvb_usb_device_properties gp8psk_properties = {
 	.usb_ctrl = CYPRESS_FX2,
 	.firmware = "dvb-usb-gp8psk-01.fw",
 
+	.size_of_priv = sizeof(struct gp8psk_state),
+
 	.num_adapters = 1,
 	.adapter = {
 		{

index fa215ad37f7b..a745cf636846 100644
@@ -60,6 +60,9 @@ int gp8psk_usb_in_op(struct dvb_usb_device *d, u8 req, u16 value, u16 index, u8
 	struct gp8psk_state *st = d->priv;
 	int ret = 0,try = 0;
 
+	if (blen > sizeof(st->data))
+		return -EIO;
+
 	if ((ret = mutex_lock_interruptible(&d->usb_mutex)))
 		return ret;
 

@@ -98,6 +101,9 @@ int gp8psk_usb_out_op(struct dvb_usb_device *d, u8 req, u16 value,
 	deb_xfer("out: req. %x, val: %x, ind: %x, buffer: ",req,value,index);
 	debug_dump(b,blen,deb_xfer);
 
+	if (blen > sizeof(st->data))
+		return -EIO;
+
 	if ((ret = mutex_lock_interruptible(&d->usb_mutex)))
 		return ret;
 

@@ -151,6 +157,11 @@ static int gp8psk_load_bcm4500fw(struct dvb_usb_device *d)
 			err("failed to load bcm4500 firmware.");
 			goto out_free;
 		}
+		if (buflen > 64) {
+			err("firmare chunk size bigger than 64 bytes.");
+			goto out_free;
+		}
+
 		memcpy(buf, ptr, buflen);
 		if (dvb_usb_generic_write(d, buf, buflen)) {
 			err("failed to load bcm4500 firmware.");

index fc7569e2728d..26d7188a1163 100644
@@ -74,22 +74,29 @@ static struct rc_map_table rc_map_haupp_table[] = {
  */
 static int nova_t_rc_query(struct dvb_usb_device *d, u32 *event, int *state)
 {
-	u8 key[5],cmd[2] = { DIBUSB_REQ_POLL_REMOTE, 0x35 }, data,toggle,custom;
+	u8 *buf, data, toggle, custom;
 	u16 raw;
 	int i;
 	struct dibusb_device_state *st = d->priv;
 
-	dvb_usb_generic_rw(d,cmd,2,key,5,0);
+	buf = kmalloc(5, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	buf[0] = DIBUSB_REQ_POLL_REMOTE;
+	buf[1] = 0x35;
+	dvb_usb_generic_rw(d, buf, 2, buf, 5, 0);
 
 	*state = REMOTE_NO_KEY_PRESSED;
-	switch (key[0]) {
+	switch (buf[0]) {
 		case DIBUSB_RC_HAUPPAUGE_KEY_PRESSED:
-			raw = ((key[1] << 8) | key[2]) >> 3;
+			raw = ((buf[1] << 8) | buf[2]) >> 3;
 			toggle = !!(raw & 0x800);
 			data = raw & 0x3f;
 			custom = (raw >> 6) & 0x1f;
 
-			deb_rc("raw key code 0x%02x, 0x%02x, 0x%02x to c: %02x d: %02x toggle: %d\n",key[1],key[2],key[3],custom,data,toggle);
+			deb_rc("raw key code 0x%02x, 0x%02x, 0x%02x to c: %02x d: %02x toggle: %d\n",
+			       buf[1], buf[2], buf[3], custom, data, toggle);
 
 			for (i = 0; i < ARRAY_SIZE(rc_map_haupp_table); i++) {
 				if (rc5_data(&rc_map_haupp_table[i]) == data &&

@@ -117,6 +124,7 @@ static int nova_t_rc_query(struct dvb_usb_device *d, u32 *event, int *state)
 			break;
 	}
 
+	kfree(buf);
 	return 0;
 }
 

index c05de1b088a4..58b685094904 100644
@@ -97,13 +97,14 @@ struct pctv452e_state {
 	u8 c;	   /* transaction counter, wraps around...  */
 	u8 initialized; /* set to 1 if 0x15 has been sent */
 	u16 last_rc_key;
+
+	unsigned char data[80];
 };
 
 static int tt3650_ci_msg(struct dvb_usb_device *d, u8 cmd, u8 *data,
 			 unsigned int write_len, unsigned int read_len)
 {
 	struct pctv452e_state *state = (struct pctv452e_state *)d->priv;
-	u8 buf[64];
 	u8 id;
 	unsigned int rlen;
 	int ret;

@@ -112,33 +113,36 @@ static int tt3650_ci_msg(struct dvb_usb_device *d, u8 cmd, u8 *data,
 	BUG_ON(write_len > 64 - 4);
 	BUG_ON(read_len > 64 - 4);
 
+	mutex_lock(&state->ca_mutex);
 	id = state->c++;
 
-	buf[0] = SYNC_BYTE_OUT;
-	buf[1] = id;
-	buf[2] = cmd;
-	buf[3] = write_len;
+	state->data[0] = SYNC_BYTE_OUT;
+	state->data[1] = id;
+	state->data[2] = cmd;
+	state->data[3] = write_len;
 
-	memcpy(buf + 4, data, write_len);
+	memcpy(state->data + 4, data, write_len);
 
 	rlen = (read_len > 0) ? 64 : 0;
-	ret = dvb_usb_generic_rw(d, buf, 4 + write_len,
-				  buf, rlen, /* delay_ms */ 0);
+	ret = dvb_usb_generic_rw(d, state->data, 4 + write_len,
+				  state->data, rlen, /* delay_ms */ 0);
 	if (0 != ret)
 		goto failed;
 
 	ret = -EIO;
-	if (SYNC_BYTE_IN != buf[0] || id != buf[1])
+	if (SYNC_BYTE_IN != state->data[0] || id != state->data[1])
 		goto failed;
 
-	memcpy(data, buf + 4, read_len);
+	memcpy(data, state->data + 4, read_len);
 
+	mutex_unlock(&state->ca_mutex);
 	return 0;
 
 failed:
 	err("CI error %d; %02X %02X %02X -> %*ph.",
-	     ret, SYNC_BYTE_OUT, id, cmd, 3, buf);
+	     ret, SYNC_BYTE_OUT, id, cmd, 3, state->data);
 
+	mutex_unlock(&state->ca_mutex);
 	return ret;
 }
 

@@ -405,52 +409,53 @@ static int pctv452e_i2c_msg(struct dvb_usb_device *d, u8 addr,
 				u8 *rcv_buf, u8 rcv_len)
 {
 	struct pctv452e_state *state = (struct pctv452e_state *)d->priv;
-	u8 buf[64];
 	u8 id;
 	int ret;
 
+	mutex_lock(&state->ca_mutex);
 	id = state->c++;
 
 	ret = -EINVAL;
 	if (snd_len > 64 - 7 || rcv_len > 64 - 7)
 		goto failed;
 
-	buf[0] = SYNC_BYTE_OUT;
-	buf[1] = id;
-	buf[2] = PCTV_CMD_I2C;
-	buf[3] = snd_len + 3;
-	buf[4] = addr << 1;
-	buf[5] = snd_len;
-	buf[6] = rcv_len;
+	state->data[0] = SYNC_BYTE_OUT;
+	state->data[1] = id;
+	state->data[2] = PCTV_CMD_I2C;
+	state->data[3] = snd_len + 3;
+	state->data[4] = addr << 1;
+	state->data[5] = snd_len;
+	state->data[6] = rcv_len;
 
-	memcpy(buf + 7, snd_buf, snd_len);
+	memcpy(state->data + 7, snd_buf, snd_len);
 
-	ret = dvb_usb_generic_rw(d, buf, 7 + snd_len,
-				  buf, /* rcv_len */ 64,
+	ret = dvb_usb_generic_rw(d, state->data, 7 + snd_len,
+				  state->data, /* rcv_len */ 64,
 				  /* delay_ms */ 0);
 	if (ret < 0)
 		goto failed;
 
 	/* TT USB protocol error. */
 	ret = -EIO;
-	if (SYNC_BYTE_IN != buf[0] || id != buf[1])
+	if (SYNC_BYTE_IN != state->data[0] || id != state->data[1])
 		goto failed;
 
 	/* I2C device didn't respond as expected. */
 	ret = -EREMOTEIO;
-	if (buf[5] < snd_len || buf[6] < rcv_len)
+	if (state->data[5] < snd_len || state->data[6] < rcv_len)
 		goto failed;
 
-	memcpy(rcv_buf, buf + 7, rcv_len);
+	memcpy(rcv_buf, state->data + 7, rcv_len);
+	mutex_unlock(&state->ca_mutex);
 
 	return rcv_len;
 
 failed:
-	err("I2C error %d; %02X %02X  %02X %02X %02X -> "
-	     "%02X %02X  %02X %02X %02X.",
+	err("I2C error %d; %02X %02X  %02X %02X %02X -> %*ph",
 	     ret, SYNC_BYTE_OUT, id, addr << 1, snd_len, rcv_len,
-	     buf[0], buf[1], buf[4], buf[5], buf[6]);
+	     7, state->data);
 
+	mutex_unlock(&state->ca_mutex);
 	return ret;
 }
 

@@ -499,8 +504,7 @@ static u32 pctv452e_i2c_func(struct i2c_adapter *adapter)
 static int pctv452e_power_ctrl(struct dvb_usb_device *d, int i)
 {
 	struct pctv452e_state *state = (struct pctv452e_state *)d->priv;
-	u8 b0[] = { 0xaa, 0, PCTV_CMD_RESET, 1, 0 };
-	u8 rx[PCTV_ANSWER_LEN];
+	u8 *rx;
 	int ret;
 
 	info("%s: %d\n", __func__, i);

@@ -511,6 +515,11 @@ static int pctv452e_power_ctrl(struct dvb_usb_device *d, int i)
 	if (state->initialized)
 		return 0;
 
+	rx = kmalloc(PCTV_ANSWER_LEN, GFP_KERNEL);
+	if (!rx)
+		return -ENOMEM;
+
+	mutex_lock(&state->ca_mutex);
 	/* hmm where shoud this should go? */
 	ret = usb_set_interface(d->udev, 0, ISOC_INTERFACE_ALTERNATIVE);
 	if (ret != 0)

@@ -518,65 +527,75 @@ static int pctv452e_power_ctrl(struct dvb_usb_device *d, int i)
 			__func__, ret);
 
 	/* this is a one-time initialization, dont know where to put */
-	b0[1] = state->c++;
+	state->data[0] = 0xaa;
+	state->data[1] = state->c++;
+	state->data[2] = PCTV_CMD_RESET;
+	state->data[3] = 1;
+	state->data[4] = 0;
 	/* reset board */
-	ret = dvb_usb_generic_rw(d, b0, sizeof(b0), rx, PCTV_ANSWER_LEN, 0);
+	ret = dvb_usb_generic_rw(d, state->data, 5, rx, PCTV_ANSWER_LEN, 0);
 	if (ret)
-		return ret;
+		goto ret;
 
-	b0[1] = state->c++;
-	b0[4] = 1;
+	state->data[1] = state->c++;
+	state->data[4] = 1;
 	/* reset board (again?) */
-	ret = dvb_usb_generic_rw(d, b0, sizeof(b0), rx, PCTV_ANSWER_LEN, 0);
+	ret = dvb_usb_generic_rw(d, state->data, 5, rx, PCTV_ANSWER_LEN, 0);
 	if (ret)
-		return ret;
+		goto ret;
 
 	state->initialized = 1;
 
-	return 0;
+ret:
+	mutex_unlock(&state->ca_mutex);
+	kfree(rx);
+	return ret;
 }
 
 static int pctv452e_rc_query(struct dvb_usb_device *d)
 {
 	struct pctv452e_state *state = (struct pctv452e_state *)d->priv;
-	u8 b[CMD_BUFFER_SIZE];
-	u8 rx[PCTV_ANSWER_LEN];
 	int ret, i;
-	u8 id = state->c++;
+	u8 id;
+
+	mutex_lock(&state->ca_mutex);
+	id = state->c++;
 
 	/* prepare command header  */
-	b[0] = SYNC_BYTE_OUT;
-	b[1] = id;
-	b[2] = PCTV_CMD_IR;
-	b[3] = 0;
+	state->data[0] = SYNC_BYTE_OUT;
+	state->data[1] = id;
+	state->data[2] = PCTV_CMD_IR;
+	state->data[3] = 0;
 
 	/* send ir request */
-	ret = dvb_usb_generic_rw(d, b, 4, rx, PCTV_ANSWER_LEN, 0);
+	ret = dvb_usb_generic_rw(d, state->data, 4,
+				 state->data, PCTV_ANSWER_LEN, 0);
 	if (ret != 0)
-		return ret;
+		goto ret;
 
 	if (debug > 3) {
-		info("%s: read: %2d: %*ph: ", __func__, ret, 3, rx);
-		for (i = 0; (i < rx[3]) && ((i+3) < PCTV_ANSWER_LEN); i++)
-			info(" %02x", rx[i+3]);
+		info("%s: read: %2d: %*ph: ", __func__, ret, 3, state->data);
+		for (i = 0; (i < state->data[3]) && ((i + 3) < PCTV_ANSWER_LEN); i++)
+			info(" %02x", state->data[i + 3]);
 
 		info("\n");
 	}
 
-	if ((rx[3] == 9) &&  (rx[12] & 0x01)) {
+	if ((state->data[3] == 9) &&  (state->data[12] & 0x01)) {
 		/* got a "press" event */
-		state->last_rc_key = RC_SCANCODE_RC5(rx[7], rx[6]);
+		state->last_rc_key = RC_SCANCODE_RC5(state->data[7], state->data[6]);
 		if (debug > 2)
 			info("%s: cmd=0x%02x sys=0x%02x\n",
-				__func__, rx[6], rx[7]);
+				__func__, state->data[6], state->data[7]);
 
 		rc_keydown(d->rc_dev, RC_TYPE_RC5, state->last_rc_key, 0);
 	} else if (state->last_rc_key) {
 		rc_keyup(d->rc_dev);
 		state->last_rc_key = 0;
 	}
-
-	return 0;
+ret:
+	mutex_unlock(&state->ca_mutex);
+	return ret;
 }
 
 static int pctv452e_read_mac_address(struct dvb_usb_device *d, u8 mac[6])

index 58b685094904..7ad0006c5ae0 100644
@@ -109,9 +109,10 @@ static int tt3650_ci_msg(struct dvb_usb_device *d, u8 cmd, u8 *data,
 	unsigned int rlen;
 	int ret;
 
-	BUG_ON(NULL == data && 0 != (write_len | read_len));
-	BUG_ON(write_len > 64 - 4);
-	BUG_ON(read_len > 64 - 4);
+	if (!data || (write_len > 64 - 4) || (read_len > 64 - 4)) {
+		err("%s: transfer data invalid", __func__);
+		return -EIO;
+	};
 
 	mutex_lock(&state->ca_mutex);
 	id = state->c++;

index d9f3262bf071..4706628a3ed5 100644
@@ -89,9 +89,13 @@ struct technisat_usb2_state {
 static int technisat_usb2_i2c_access(struct usb_device *udev,
 		u8 device_addr, u8 *tx, u8 txlen, u8 *rx, u8 rxlen)
 {
-	u8 b[64];
+	u8 *b;
 	int ret, actual_length;
 
+	b = kmalloc(64, GFP_KERNEL);
+	if (!b)
+		return -ENOMEM;
+
 	deb_i2c("i2c-access: %02x, tx: ", device_addr);
 	debug_dump(tx, txlen, deb_i2c);
 	deb_i2c(" ");

@@ -123,7 +127,7 @@ static int technisat_usb2_i2c_access(struct usb_device *udev,
 
 	if (ret < 0) {
 		err("i2c-error: out failed %02x = %d", device_addr, ret);
-		return -ENODEV;
+		goto err;
 	}
 
 	ret = usb_bulk_msg(udev,

@@ -131,7 +135,7 @@ static int technisat_usb2_i2c_access(struct usb_device *udev,
 			b, 64, &actual_length, 1000);
 	if (ret < 0) {
 		err("i2c-error: in failed %02x = %d", device_addr, ret);
-		return -ENODEV;
+		goto err;
 	}
 
 	if (b[0] != I2C_STATUS_OK) {

@@ -140,7 +144,7 @@ static int technisat_usb2_i2c_access(struct usb_device *udev,
 		if (!(b[0] == I2C_STATUS_NAK &&
 				device_addr == 0x60
 				/* && device_is_technisat_usb2 */))
-			return -ENODEV;
+			goto err;
 	}
 
 	deb_i2c("status: %d, ", b[0]);

@@ -154,7 +158,9 @@ static int technisat_usb2_i2c_access(struct usb_device *udev,
 
 	deb_i2c("\n");
 
-	return 0;
+err:
+	kfree(b);
+	return ret;
 }
 
 static int technisat_usb2_i2c_xfer(struct i2c_adapter *adap, struct i2c_msg *msg,

index 639c4678c65b..1448c3d27ea2 100644
@@ -462,8 +462,10 @@ extern int dvb_usb_device_init(struct usb_interface *,
 extern void dvb_usb_device_exit(struct usb_interface *);
 
 /* the generic read/write method for device control */
-extern int dvb_usb_generic_rw(struct dvb_usb_device *, u8 *, u16, u8 *, u16,int);
-extern int dvb_usb_generic_write(struct dvb_usb_device *, u8 *, u16);
+extern int __must_check
+dvb_usb_generic_rw(struct dvb_usb_device *, u8 *, u16, u8 *, u16, int);
+extern int __must_check
+dvb_usb_generic_write(struct dvb_usb_device *, u8 *, u16);
 
 /* commonly used remote control parsing */
 extern int dvb_usb_nec_rc_key_to_event(struct dvb_usb_device *, u8[], u32 *, int *);

index 26d7188a1163..1babd3341910 100644
@@ -76,7 +76,7 @@ static int nova_t_rc_query(struct dvb_usb_device *d, u32 *event, int *state)
 {
 	u8 *buf, data, toggle, custom;
 	u16 raw;
-	int i;
+	int i, ret;
 	struct dibusb_device_state *st = d->priv;
 
 	buf = kmalloc(5, GFP_KERNEL);

@@ -85,7 +85,9 @@ static int nova_t_rc_query(struct dvb_usb_device *d, u32 *event, int *state)
 
 	buf[0] = DIBUSB_REQ_POLL_REMOTE;
 	buf[1] = 0x35;
-	dvb_usb_generic_rw(d, buf, 2, buf, 5, 0);
+	ret = dvb_usb_generic_rw(d, buf, 2, buf, 5, 0);
+	if (ret < 0)
+		goto ret;
 
 	*state = REMOTE_NO_KEY_PRESSED;
 	switch (buf[0]) {

@@ -124,8 +126,9 @@ static int nova_t_rc_query(struct dvb_usb_device *d, u32 *event, int *state)
 			break;
 	}
 
+ret:
 	kfree(buf);
-	return 0;
+	return ret;
 }
 
 static int nova_t_read_mac_address (struct dvb_usb_device *d, u8 mac[6])

index 5fb0c650926e..2c720cb2fb00 100644
@@ -852,7 +852,7 @@ static int su3000_power_ctrl(struct dvb_usb_device *d, int i)
 	if (i && !state->initialized) {
 		state->initialized = 1;
 		/* reset board */
-		dvb_usb_generic_rw(d, obuf, 2, NULL, 0, 0);
+		return dvb_usb_generic_rw(d, obuf, 2, NULL, 0, 0);
 	}
 
 	return 0;

index 09f8c28bd4db..4284f6984dc1 100644
@@ -29,7 +29,9 @@ static int digitv_ctrl_msg(struct dvb_usb_device *d,
 		u8 cmd, u8 vv, u8 *wbuf, int wlen, u8 *rbuf, int rlen)
 {
 	struct digitv_state *st = d->priv;
-	int wo = (rbuf == NULL || rlen == 0); /* write-only */
+	int ret, wo;
+
+	wo = (rbuf == NULL || rlen == 0); /* write-only */
 
 	memset(st->sndbuf, 0, 7);
 	memset(st->rcvbuf, 0, 7);

@@ -40,12 +42,12 @@ static int digitv_ctrl_msg(struct dvb_usb_device *d,
 
 	if (wo) {
 		memcpy(&st->sndbuf[3], wbuf, wlen);
-		dvb_usb_generic_write(d, st->sndbuf, 7);
+		ret = dvb_usb_generic_write(d, st->sndbuf, 7);
 	} else {
-		dvb_usb_generic_rw(d, st->sndbuf, 7, st->rcvbuf, 7, 10);
+		ret = dvb_usb_generic_rw(d, st->sndbuf, 7, st->rcvbuf, 7, 10);
 		memcpy(rbuf, &st->rcvbuf[3], rlen);
 	}
-	return 0;
+	return ret;
 }
 
 /* I2C */