Merge commit 'v2.6.30-rc5' into x86/mm

Merge reason: this branch was on a .30-rc2 base - sync it up with
              all the latest fixes.

Signed-off-by: Ingo Molnar <mingo@elte.hu>

19 files changed, 112 insertions, 162 deletions

diff --git a/drivers/usb/serial/cyberjack.c b/drivers/usb/serial/cyberjack.c
index 858bdd038fb..dd501bb63ed 100644
--- a/drivers/usb/serial/cyberjack.c
+++ b/drivers/usb/serial/cyberjack.c
@@ -175,13 +175,6 @@ static int  cyberjack_open(struct tty_struct *tty,
 	dbg("%s - usb_clear_halt", __func__);
 	usb_clear_halt(port->serial->dev, port->write_urb->pipe);
 
-	/* force low_latency on so that our tty_push actually forces
-	 * the data through, otherwise it is scheduled, and with high
-	 * data rates (like with OHCI) data can get lost.
-	 */
-	if (tty)
-		tty->low_latency = 1;
-
 	priv = usb_get_serial_port_data(port);
 	spin_lock_irqsave(&priv->lock, flags);
 	priv->rdtodo = 0;
diff --git a/drivers/usb/serial/cypress_m8.c b/drivers/usb/serial/cypress_m8.c
index eae4740d448..e568710b263 100644
--- a/drivers/usb/serial/cypress_m8.c
+++ b/drivers/usb/serial/cypress_m8.c
@@ -656,10 +656,6 @@ static int cypress_open(struct tty_struct *tty,
 	priv->rx_flags = 0;
 	spin_unlock_irqrestore(&priv->lock, flags);
 
-	/* setting to zero could cause data loss */
-	if (tty)
-		tty->low_latency = 1;
-
 	/* raise both lines and set termios */
 	spin_lock_irqsave(&priv->lock, flags);
 	priv->line_control = CONTROL_DTR | CONTROL_RTS;
diff --git a/drivers/usb/serial/empeg.c b/drivers/usb/serial/empeg.c
index 8a69cce40b6..c709ec474a8 100644
--- a/drivers/usb/serial/empeg.c
+++ b/drivers/usb/serial/empeg.c
@@ -478,12 +478,6 @@ static void empeg_set_termios(struct tty_struct *tty,
 	termios->c_cflag
 		|= CS8;		/* character size 8 bits */
 
-	/*
-	 * Force low_latency on; otherwise the pushes are scheduled;
-	 * this is bad as it opens up the possibility of dropping bytes
-	 * on the floor.  We don't want to drop bytes on the floor. :)
-	 */
-	tty->low_latency = 1;
 	tty_encode_baud_rate(tty, 115200, 115200);
 }
 
diff --git a/drivers/usb/serial/garmin_gps.c b/drivers/usb/serial/garmin_gps.c
index a26a0e2cdb4..586d30ff450 100644
--- a/drivers/usb/serial/garmin_gps.c
+++ b/drivers/usb/serial/garmin_gps.c
@@ -973,14 +973,6 @@ static int garmin_open(struct tty_struct *tty,
 
 	dbg("%s - port %d", __func__, port->number);
 
-	/*
-	 * Force low_latency on so that our tty_push actually forces the data
-	 * through, otherwise it is scheduled, and with high data rates (like
-	 * with OHCI) data can get lost.
-	 */
-	if (tty)
-		tty->low_latency = 1;
-
 	spin_lock_irqsave(&garmin_data_p->lock, flags);
 	garmin_data_p->mode  = initial_mode;
 	garmin_data_p->count = 0;
diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c
index 9d57cace373..4cec9906ccf 100644
--- a/drivers/usb/serial/generic.c
+++ b/drivers/usb/serial/generic.c
@@ -122,12 +122,6 @@ int usb_serial_generic_open(struct tty_struct *tty,
 
 	dbg("%s - port %d", __func__, port->number);
 
-	/* force low_latency on so that our tty_push actually forces the data
-	   through, otherwise it is scheduled, and with high data rates (like
-	   with OHCI) data can get lost. */
-	if (tty)
-		tty->low_latency = 1;
-
 	/* clear the throttle flags */
 	spin_lock_irqsave(&port->lock, flags);
 	port->throttled = 0;
diff --git a/drivers/usb/serial/io_edgeport.c b/drivers/usb/serial/io_edgeport.c
index e85c8c0d1ad..fb4a73d090f 100644
--- a/drivers/usb/serial/io_edgeport.c
+++ b/drivers/usb/serial/io_edgeport.c
@@ -193,8 +193,6 @@ static const struct divisor_table_entry divisor_table[] = {
 /* local variables */
 static int debug;
 
-static int low_latency = 1;	/* tty low latency flag, on by default */
-
 static atomic_t CmdUrbs;	/* Number of outstanding Command Write Urbs */
 
 
@@ -867,9 +865,6 @@ static int edge_open(struct tty_struct *tty,
 	if (edge_port == NULL)
 		return -ENODEV;
 
-	if (tty)
-		tty->low_latency = low_latency;
-
 	/* see if we've set up our endpoint info yet (can't set it up
 	   in edge_startup as the structures were not set up at that time.) */
 	serial = port->serial;
@@ -3299,6 +3294,3 @@ MODULE_FIRMWARE("edgeport/down2.fw");
 
 module_param(debug, bool, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(debug, "Debug enabled or not");
-
-module_param(low_latency, bool, S_IRUGO | S_IWUSR);
-MODULE_PARM_DESC(low_latency, "Low latency enabled or not");
diff --git a/drivers/usb/serial/io_ti.c b/drivers/usb/serial/io_ti.c
index c3cdd00ddc4..513b25e044c 100644
--- a/drivers/usb/serial/io_ti.c
+++ b/drivers/usb/serial/io_ti.c
@@ -76,7 +76,6 @@ struct edgeport_uart_buf_desc {
 #define EDGE_READ_URB_STOPPING	1
 #define EDGE_READ_URB_STOPPED	2
 
-#define EDGE_LOW_LATENCY	1
 #define EDGE_CLOSING_WAIT	4000	/* in .01 sec */
 
 #define EDGE_OUT_BUF_SIZE	1024
@@ -232,7 +231,6 @@ static unsigned short OperationalBuildNumber;
 
 static int debug;
 
-static int low_latency = EDGE_LOW_LATENCY;
 static int closing_wait = EDGE_CLOSING_WAIT;
 static int ignore_cpu_rev;
 static int default_uart_mode;		/* RS232 */
@@ -1850,9 +1848,6 @@ static int edge_open(struct tty_struct *tty,
 	if (edge_port == NULL)
 		return -ENODEV;
 
-	if (tty)
-		tty->low_latency = low_latency;
-
 	port_number = port->number - port->serial->minor;
 	switch (port_number) {
 	case 0:
@@ -3008,9 +3003,6 @@ MODULE_FIRMWARE("edgeport/down3.bin");
 module_param(debug, bool, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(debug, "Debug enabled or not");
 
-module_param(low_latency, bool, S_IRUGO | S_IWUSR);
-MODULE_PARM_DESC(low_latency, "Low latency enabled or not");
-
 module_param(closing_wait, int, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(closing_wait, "Maximum wait for data to drain, in .01 secs");
 
diff --git a/drivers/usb/serial/ipaq.c b/drivers/usb/serial/ipaq.c
index ef92095b073..cd62825a9ac 100644
--- a/drivers/usb/serial/ipaq.c
+++ b/drivers/usb/serial/ipaq.c
@@ -631,13 +631,7 @@ static int ipaq_open(struct tty_struct *tty,
 		priv->free_len += PACKET_SIZE;
 	}
 
-	/*
-	 * Force low latency on. This will immediately push data to the line
-	 * discipline instead of queueing.
-	 */
-
 	if (tty) {
-		tty->low_latency = 1;
 		/* FIXME: These two are bogus */
 		tty->raw = 1;
 		tty->real_raw = 1;
diff --git a/drivers/usb/serial/ipw.c b/drivers/usb/serial/ipw.c
index f530032ed93..da2a2b46644 100644
--- a/drivers/usb/serial/ipw.c
+++ b/drivers/usb/serial/ipw.c
@@ -207,9 +207,6 @@ static int ipw_open(struct tty_struct *tty,
 	if (!buf_flow_init)
 		return -ENOMEM;
 
-	if (tty)
-		tty->low_latency = 1;
-
 	/* --1: Tell the modem to initialize (we think) From sniffs this is
 	 *	always the first thing that gets sent to the modem during
 	 *	opening of the device */
diff --git a/drivers/usb/serial/iuu_phoenix.c b/drivers/usb/serial/iuu_phoenix.c
index 2314c6ae4fc..4473d442b2a 100644
--- a/drivers/usb/serial/iuu_phoenix.c
+++ b/drivers/usb/serial/iuu_phoenix.c
@@ -1051,7 +1051,6 @@ static int iuu_open(struct tty_struct *tty,
 		tty->termios->c_oflag = 0;
 		tty->termios->c_iflag = 0;
 		priv->termios_initialized = 1;
-		tty->low_latency = 1;
 		priv->poll = 0;
 	 }
 	spin_unlock_irqrestore(&priv->lock, flags);
diff --git a/drivers/usb/serial/kobil_sct.c b/drivers/usb/serial/kobil_sct.c
index 6286baad939..c148544953b 100644
--- a/drivers/usb/serial/kobil_sct.c
+++ b/drivers/usb/serial/kobil_sct.c
@@ -231,13 +231,7 @@ static int kobil_open(struct tty_struct *tty,
 	/* someone sets the dev to 0 if the close method has been called */
 	port->interrupt_in_urb->dev = port->serial->dev;
 
-
-	/* force low_latency on so that our tty_push actually forces
-	 * the data through, otherwise it is scheduled, and with high
-	 * data rates (like with OHCI) data can get lost.
-	 */
 	if (tty) {
-		tty->low_latency = 1;
 
 		/* Default to echo off and other sane device settings */
 		tty->termios->c_lflag = 0;
diff --git a/drivers/usb/serial/mos7720.c b/drivers/usb/serial/mos7720.c
index e772cc0a97f..24e3b5d4b4d 100644
--- a/drivers/usb/serial/mos7720.c
+++ b/drivers/usb/serial/mos7720.c
@@ -446,13 +446,6 @@ static int mos7720_open(struct tty_struct *tty,
 	data = 0x0c;
 	send_mos_cmd(serial, MOS_WRITE, port_number, 0x01, &data);
 
-	/* force low_latency on so that our tty_push actually forces *
-	 * the data through,otherwise it is scheduled, and with      *
-	 * high data rates (like with OHCI) data can get lost.       */
-
-	if (tty)
-		tty->low_latency = 1;
-
 	/* see if we've set up our endpoint info yet   *
 	 * (can't set it up in mos7720_startup as the  *
 	 * structures were not set up at that time.)   */
diff --git a/drivers/usb/serial/mos7840.c b/drivers/usb/serial/mos7840.c
index 2c20e88a91b..84fb1dcd30d 100644
--- a/drivers/usb/serial/mos7840.c
+++ b/drivers/usb/serial/mos7840.c
@@ -38,7 +38,7 @@
 /*
  * Version Information
  */
-#define DRIVER_VERSION "1.3.1"
+#define DRIVER_VERSION "1.3.2"
 #define DRIVER_DESC "Moschip 7840/7820 USB Serial Driver"
 
 /*
@@ -123,6 +123,11 @@
 #define BANDB_DEVICE_ID_USOPTL4_4       0xAC44
 #define BANDB_DEVICE_ID_USOPTL4_2       0xAC42
 
+/* This driver also supports the ATEN UC2324 device since it is mos7840 based
+ *  - if I knew the device id it would also support the ATEN UC2322 */
+#define USB_VENDOR_ID_ATENINTL		0x0557
+#define ATENINTL_DEVICE_ID_UC2324	0x2011
+
 /* Interrupt Routine Defines    */
 
 #define SERIAL_IIR_RLS      0x06
@@ -170,6 +175,7 @@ static struct usb_device_id moschip_port_id_table[] = {
 	{USB_DEVICE(USB_VENDOR_ID_MOSCHIP, MOSCHIP_DEVICE_ID_7820)},
 	{USB_DEVICE(USB_VENDOR_ID_BANDB, BANDB_DEVICE_ID_USOPTL4_4)},
 	{USB_DEVICE(USB_VENDOR_ID_BANDB, BANDB_DEVICE_ID_USOPTL4_2)},
+	{USB_DEVICE(USB_VENDOR_ID_ATENINTL, ATENINTL_DEVICE_ID_UC2324)},
 	{}			/* terminating entry */
 };
 
@@ -178,6 +184,7 @@ static __devinitdata struct usb_device_id moschip_id_table_combined[] = {
 	{USB_DEVICE(USB_VENDOR_ID_MOSCHIP, MOSCHIP_DEVICE_ID_7820)},
 	{USB_DEVICE(USB_VENDOR_ID_BANDB, BANDB_DEVICE_ID_USOPTL4_4)},
 	{USB_DEVICE(USB_VENDOR_ID_BANDB, BANDB_DEVICE_ID_USOPTL4_2)},
+	{USB_DEVICE(USB_VENDOR_ID_ATENINTL, ATENINTL_DEVICE_ID_UC2324)},
 	{}			/* terminating entry */
 };
 
@@ -1000,12 +1007,6 @@ static int mos7840_open(struct tty_struct *tty,
 	status = mos7840_set_reg_sync(port, mos7840_port->ControlRegOffset,
 									Data);
 
-	/* force low_latency on so that our tty_push actually forces *
-	 * the data through,otherwise it is scheduled, and with      *
-	 * high data rates (like with OHCI) data can get lost.       */
-	if (tty)
-		tty->low_latency = 1;
-
 	/* Check to see if we've set up our endpoint info yet    *
 	 * (can't set it up in mos7840_startup as the structures *
 	 * were not set up at that time.)                        */
@@ -2477,9 +2478,14 @@ static int mos7840_startup(struct usb_serial *serial)
 		mos7840_set_port_private(serial->port[i], mos7840_port);
 		spin_lock_init(&mos7840_port->pool_lock);
 
-		mos7840_port->port_num = ((serial->port[i]->number -
-					   (serial->port[i]->serial->minor)) +
-					  1);
+		/* minor is not initialised until later by
+		 * usb-serial.c:get_free_serial() and cannot therefore be used
+		 * to index device instances */
+		mos7840_port->port_num = i + 1;
+		dbg ("serial->port[i]->number = %d", serial->port[i]->number);
+		dbg ("serial->port[i]->serial->minor = %d", serial->port[i]->serial->minor);
+		dbg ("mos7840_port->port_num = %d", mos7840_port->port_num);
+		dbg ("serial->minor = %d", serial->minor);
 
 		if (mos7840_port->port_num == 1) {
 			mos7840_port->SpRegOffset = 0x0;
@@ -2690,13 +2696,16 @@ static void mos7840_shutdown(struct usb_serial *serial)
 
 	for (i = 0; i < serial->num_ports; ++i) {
 		mos7840_port = mos7840_get_port_private(serial->port[i]);
-		spin_lock_irqsave(&mos7840_port->pool_lock, flags);
-		mos7840_port->zombie = 1;
-		spin_unlock_irqrestore(&mos7840_port->pool_lock, flags);
-		usb_kill_urb(mos7840_port->control_urb);
-		kfree(mos7840_port->ctrl_buf);
-		kfree(mos7840_port->dr);
-		kfree(mos7840_port);
+		dbg ("mos7840_port %d = %p", i, mos7840_port);
+		if (mos7840_port) {
+			spin_lock_irqsave(&mos7840_port->pool_lock, flags);
+			mos7840_port->zombie = 1;
+			spin_unlock_irqrestore(&mos7840_port->pool_lock, flags);
+			usb_kill_urb(mos7840_port->control_urb);
+			kfree(mos7840_port->ctrl_buf);
+			kfree(mos7840_port->dr);
+			kfree(mos7840_port);
+		}
 		mos7840_set_port_private(serial->port[i], NULL);
 	}
 
diff --git a/drivers/usb/serial/opticon.c b/drivers/usb/serial/opticon.c
index 839583dc8b6..b500ad10b75 100644
--- a/drivers/usb/serial/opticon.c
+++ b/drivers/usb/serial/opticon.c
@@ -159,14 +159,6 @@ static int opticon_open(struct tty_struct *tty, struct usb_serial_port *port,
 	priv->port = port;
 	spin_unlock_irqrestore(&priv->lock, flags);
 
-	/*
-	 * Force low_latency on so that our tty_push actually forces the data
-	 * through, otherwise it is scheduled, and with high data rates (like
-	 * with OHCI) data can get lost.
-	 */
-	if (tty)
-		tty->low_latency = 1;
-
 	/* Start reading from the device */
 	usb_fill_bulk_urb(priv->bulk_read_urb, priv->udev,
 			  usb_rcvbulkpipe(priv->udev,
diff --git a/drivers/usb/serial/option.c b/drivers/usb/serial/option.c
index 47bd070f24b..7817b82889c 100644
--- a/drivers/usb/serial/option.c
+++ b/drivers/usb/serial/option.c
@@ -936,9 +936,6 @@ static int option_open(struct tty_struct *tty,
 				usb_pipeout(urb->pipe), 0); */
 	}
 
-	if (tty)
-		tty->low_latency = 1;
-
 	option_send_setup(tty, port);
 
 	return 0;
diff --git a/drivers/usb/serial/sierra.c b/drivers/usb/serial/sierra.c
index d9bf9a5c20e..913225c6161 100644
--- a/drivers/usb/serial/sierra.c
+++ b/drivers/usb/serial/sierra.c
@@ -14,7 +14,7 @@
   Whom based his on the Keyspan driver by Hugh Blemings <hugh@blemings.org>
 */
 
-#define DRIVER_VERSION "v.1.3.2"
+#define DRIVER_VERSION "v.1.3.3"
 #define DRIVER_AUTHOR "Kevin Lloyd <klloyd@sierrawireless.com>"
 #define DRIVER_DESC "USB Driver for Sierra Wireless USB modems"
 
@@ -259,9 +259,21 @@ static int sierra_send_setup(struct tty_struct *tty,
 			val |= 0x02;
 
 		/* If composite device then properly report interface */
-		if (serial->num_ports == 1)
+		if (serial->num_ports == 1) {
 			interface = sierra_calc_interface(serial);
 
+			/* Control message is sent only to interfaces with
+			 * interrupt_in endpoints
+			 */
+			if (port->interrupt_in_urb) {
+				/* send control message */
+				return usb_control_msg(serial->dev,
+					usb_rcvctrlpipe(serial->dev, 0),
+					0x22, 0x21, val, interface,
+					NULL, 0, USB_CTRL_SET_TIMEOUT);
+			}
+		}
+
 		/* Otherwise the need to do non-composite mapping */
 		else {
 			if (port->bulk_out_endpointAddress == 2)
@@ -270,12 +282,13 @@ static int sierra_send_setup(struct tty_struct *tty,
 				interface = 1;
 			else if (port->bulk_out_endpointAddress == 5)
 				interface = 2;
-		}
 
-		return usb_control_msg(serial->dev,
+			return usb_control_msg(serial->dev,
 				usb_rcvctrlpipe(serial->dev, 0),
 				0x22, 0x21, val, interface,
 				NULL, 0, USB_CTRL_SET_TIMEOUT);
+
+		}
 	}
 
 	return 0;
@@ -585,9 +598,6 @@ static int sierra_open(struct tty_struct *tty,
 		}
 	}
 
-	if (tty)
-		tty->low_latency = 1;
-
 	sierra_send_setup(tty, port);
 
 	/* start up the interrupt endpoint if we have one */
diff --git a/drivers/usb/serial/ti_usb_3410_5052.c b/drivers/usb/serial/ti_usb_3410_5052.c
index 9c4c700c7cc..0a64bac306e 100644
--- a/drivers/usb/serial/ti_usb_3410_5052.c
+++ b/drivers/usb/serial/ti_usb_3410_5052.c
@@ -50,11 +50,10 @@
 
 #define TI_TRANSFER_TIMEOUT	2
 
-#define TI_DEFAULT_LOW_LATENCY	0
 #define TI_DEFAULT_CLOSING_WAIT	4000		/* in .01 secs */
 
 /* supported setserial flags */
-#define TI_SET_SERIAL_FLAGS	(ASYNC_LOW_LATENCY)
+#define TI_SET_SERIAL_FLAGS	0
 
 /* read urb states */
 #define TI_READ_URB_RUNNING	0
@@ -161,7 +160,6 @@ static int ti_buf_get(struct circ_buf *cb, char *buf, int count);
 
 /* module parameters */
 static int debug;
-static int low_latency = TI_DEFAULT_LOW_LATENCY;
 static int closing_wait = TI_DEFAULT_CLOSING_WAIT;
 static ushort vendor_3410[TI_EXTRA_VID_PID_COUNT];
 static unsigned int vendor_3410_count;
@@ -296,10 +294,6 @@ MODULE_FIRMWARE("mts_edge.fw");
 module_param(debug, bool, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(debug, "Enable debugging, 0=no, 1=yes");
 
-module_param(low_latency, bool, S_IRUGO | S_IWUSR);
-MODULE_PARM_DESC(low_latency,
-		"TTY low_latency flag, 0=off, 1=on, default is off");
-
 module_param(closing_wait, int, S_IRUGO | S_IWUSR);
 MODULE_PARM_DESC(closing_wait,
     "Maximum wait for data to drain in close, in .01 secs, default is 4000");
@@ -448,7 +442,6 @@ static int ti_startup(struct usb_serial *serial)
 		spin_lock_init(&tport->tp_lock);
 		tport->tp_uart_base_addr = (i == 0 ?
 				TI_UART1_BASE_ADDR : TI_UART2_BASE_ADDR);
-		tport->tp_flags = low_latency ? ASYNC_LOW_LATENCY : 0;
 		tport->tp_closing_wait = closing_wait;
 		init_waitqueue_head(&tport->tp_msr_wait);
 		init_waitqueue_head(&tport->tp_write_wait);
@@ -528,10 +521,6 @@ static int ti_open(struct tty_struct *tty,
 	if (mutex_lock_interruptible(&tdev->td_open_close_lock))
 		return -ERESTARTSYS;
 
-	if (tty)
-		tty->low_latency =
-				(tport->tp_flags & ASYNC_LOW_LATENCY) ? 1 : 0;
-
 	port_number = port->number - port->serial->minor;
 
 	memset(&(tport->tp_icount), 0x00, sizeof(tport->tp_icount));
@@ -1454,7 +1443,6 @@ static int ti_set_serial_info(struct tty_struct *tty, struct ti_port *tport,
 		return -EFAULT;
 
 	tport->tp_flags = new_serial.flags & TI_SET_SERIAL_FLAGS;
-	tty->low_latency = (tport->tp_flags & ASYNC_LOW_LATENCY) ? 1 : 0;
 	tport->tp_closing_wait = new_serial.closing_wait;
 
 	return 0;
diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index 2a70563bbee..0a566eea49c 100644
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -137,22 +137,10 @@ static void destroy_serial(struct kref *kref)
 
 	dbg("%s - %s", __func__, serial->type->description);
 
-	serial->type->shutdown(serial);
-
 	/* return the minor range that this device had */
 	if (serial->minor != SERIAL_TTY_NO_MINOR)
 		return_serial(serial);
 
-	for (i = 0; i < serial->num_ports; ++i)
-		serial->port[i]->port.count = 0;
-
-	/* the ports are cleaned up and released in port_release() */
-	for (i = 0; i < serial->num_ports; ++i)
-		if (serial->port[i]->dev.parent != NULL) {
-			device_unregister(&serial->port[i]->dev);
-			serial->port[i] = NULL;
-		}
-
 	/* If this is a "fake" port, we have to clean it up here, as it will
 	 * not get cleaned up in port_release() as it was never registered with
 	 * the driver core */
@@ -187,7 +175,7 @@ static int serial_open (struct tty_struct *tty, struct file *filp)
 	struct usb_serial *serial;
 	struct usb_serial_port *port;
 	unsigned int portNumber;
-	int retval;
+	int retval = 0;
 
 	dbg("%s", __func__);
 
@@ -198,21 +186,24 @@ static int serial_open (struct tty_struct *tty, struct file *filp)
 		return -ENODEV;
 	}
 
+	mutex_lock(&serial->disc_mutex);
 	portNumber = tty->index - serial->minor;
 	port = serial->port[portNumber];
-	if (!port) {
-		retval = -ENODEV;
-		goto bailout_kref_put;
-	}
-
-	if (port->serial->disconnected) {
+	if (!port || serial->disconnected)
 		retval = -ENODEV;
-		goto bailout_kref_put;
-	}
+	else
+		get_device(&port->dev);
+	/*
+	 * Note: Our locking order requirement does not allow port->mutex
+	 * to be acquired while serial->disc_mutex is held.
+	 */
+	mutex_unlock(&serial->disc_mutex);
+	if (retval)
+		goto bailout_serial_put;
 
 	if (mutex_lock_interruptible(&port->mutex)) {
 		retval = -ERESTARTSYS;
-		goto bailout_kref_put;
+		goto bailout_port_put;
 	}
 
 	++port->port.count;
@@ -232,14 +223,20 @@ static int serial_open (struct tty_struct *tty, struct file *filp)
 			goto bailout_mutex_unlock;
 		}
 
-		retval = usb_autopm_get_interface(serial->interface);
+		mutex_lock(&serial->disc_mutex);
+		if (serial->disconnected)
+			retval = -ENODEV;
+		else
+			retval = usb_autopm_get_interface(serial->interface);
 		if (retval)
 			goto bailout_module_put;
+
 		/* only call the device specific open if this
 		 * is the first time the port is opened */
 		retval = serial->type->open(tty, port, filp);
 		if (retval)
 			goto bailout_interface_put;
+		mutex_unlock(&serial->disc_mutex);
 	}
 
 	mutex_unlock(&port->mutex);
@@ -248,13 +245,16 @@ static int serial_open (struct tty_struct *tty, struct file *filp)
 bailout_interface_put:
 	usb_autopm_put_interface(serial->interface);
 bailout_module_put:
+	mutex_unlock(&serial->disc_mutex);
 	module_put(serial->type->driver.owner);
 bailout_mutex_unlock:
 	port->port.count = 0;
 	tty->driver_data = NULL;
 	tty_port_tty_set(&port->port, NULL);
 	mutex_unlock(&port->mutex);
-bailout_kref_put:
+bailout_port_put:
+	put_device(&port->dev);
+bailout_serial_put:
 	usb_serial_put(serial);
 	return retval;
 }
@@ -262,6 +262,9 @@ bailout_kref_put:
 static void serial_close(struct tty_struct *tty, struct file *filp)
 {
 	struct usb_serial_port *port = tty->driver_data;
+	struct usb_serial *serial;
+	struct module *owner;
+	int count;
 
 	if (!port)
 		return;
@@ -269,6 +272,8 @@ static void serial_close(struct tty_struct *tty, struct file *filp)
 	dbg("%s - port %d", __func__, port->number);
 
 	mutex_lock(&port->mutex);
+	serial = port->serial;
+	owner = serial->type->driver.owner;
 
 	if (port->port.count == 0) {
 		mutex_unlock(&port->mutex);
@@ -281,7 +286,7 @@ static void serial_close(struct tty_struct *tty, struct file *filp)
 		 * this before we drop the port count. The call is protected
 		 * by the port mutex
 		 */
-		port->serial->type->close(tty, port, filp);
+		serial->type->close(tty, port, filp);
 
 	if (port->port.count == (port->console ? 2 : 1)) {
 		struct tty_struct *tty = tty_port_tty_get(&port->port);
@@ -295,17 +300,23 @@ static void serial_close(struct tty_struct *tty, struct file *filp)
 		}
 	}
 
-	if (port->port.count == 1) {
-		mutex_lock(&port->serial->disc_mutex);
-		if (!port->serial->disconnected)
-			usb_autopm_put_interface(port->serial->interface);
-		mutex_unlock(&port->serial->disc_mutex);
-		module_put(port->serial->type->driver.owner);
-	}
 	--port->port.count;
-
+	count = port->port.count;
 	mutex_unlock(&port->mutex);
-	usb_serial_put(port->serial);
+	put_device(&port->dev);
+
+	/* Mustn't dereference port any more */
+	if (count == 0) {
+		mutex_lock(&serial->disc_mutex);
+		if (!serial->disconnected)
+			usb_autopm_put_interface(serial->interface);
+		mutex_unlock(&serial->disc_mutex);
+	}
+	usb_serial_put(serial);
+
+	/* Mustn't dereference serial any more */
+	if (count == 0)
+		module_put(owner);
 }
 
 static int serial_write(struct tty_struct *tty, const unsigned char *buf,
@@ -549,7 +560,13 @@ static void kill_traffic(struct usb_serial_port *port)
 
 static void port_free(struct usb_serial_port *port)
 {
+	/*
+	 * Stop all the traffic before cancelling the work, so that
+	 * nobody will restart it by calling usb_serial_port_softint.
+	 */
 	kill_traffic(port);
+	cancel_work_sync(&port->work);
+
 	usb_free_urb(port->read_urb);
 	usb_free_urb(port->write_urb);
 	usb_free_urb(port->interrupt_in_urb);
@@ -558,7 +575,6 @@ static void port_free(struct usb_serial_port *port)
 	kfree(port->bulk_out_buffer);
 	kfree(port->interrupt_in_buffer);
 	kfree(port->interrupt_out_buffer);
-	flush_scheduled_work();		/* port->work */
 	kfree(port);
 }
 
@@ -1043,6 +1059,12 @@ void usb_serial_disconnect(struct usb_interface *interface)
 	usb_set_intfdata(interface, NULL);
 	/* must set a flag, to signal subdrivers */
 	serial->disconnected = 1;
+	mutex_unlock(&serial->disc_mutex);
+
+	/* Unfortunately, many of the sub-drivers expect the port structures
+	 * to exist when their shutdown method is called, so we have to go
+	 * through this awkward two-step unregistration procedure.
+	 */
 	for (i = 0; i < serial->num_ports; ++i) {
 		port = serial->port[i];
 		if (port) {
@@ -1052,11 +1074,21 @@ void usb_serial_disconnect(struct usb_interface *interface)
 				tty_kref_put(tty);
 			}
 			kill_traffic(port);
+			cancel_work_sync(&port->work);
+			device_del(&port->dev);
+		}
+	}
+	serial->type->shutdown(serial);
+	for (i = 0; i < serial->num_ports; ++i) {
+		port = serial->port[i];
+		if (port) {
+			put_device(&port->dev);
+			serial->port[i] = NULL;
 		}
 	}
+
 	/* let the last holder of this object
 	 * cause it to be cleaned up */
-	mutex_unlock(&serial->disc_mutex);
 	usb_serial_put(serial);
 	dev_info(dev, "device disconnected\n");
 }
diff --git a/drivers/usb/serial/visor.c b/drivers/usb/serial/visor.c
index 4facce3d936..5ac414bda71 100644
--- a/drivers/usb/serial/visor.c
+++ b/drivers/usb/serial/visor.c
@@ -296,14 +296,6 @@ static int visor_open(struct tty_struct *tty, struct usb_serial_port *port,
 	priv->throttled = 0;
 	spin_unlock_irqrestore(&priv->lock, flags);
 
-	/*
-	 * Force low_latency on so that our tty_push actually forces the data
-	 * through, otherwise it is scheduled, and with high data rates (like
-	 * with OHCI) data can get lost.
-	 */
-	if (tty)
-		tty->low_latency = 1;
-
 	/* Start reading from the device */
 	usb_fill_bulk_urb(port->read_urb, serial->dev,
 			   usb_rcvbulkpipe(serial->dev,