Merge commit 'v2.6.30' into for-2.6.31

21 files changed, 135 insertions, 173 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/ftdi_sio.c b/drivers/usb/serial/ftdi_sio.c
index 8100f1d2590..d9fcdaedf38 100644
--- a/drivers/usb/serial/ftdi_sio.c
+++ b/drivers/usb/serial/ftdi_sio.c
@@ -56,6 +56,7 @@ static __u16 vendor = FTDI_VID;
 static __u16 product;
 
 struct ftdi_private {
+        struct kref kref;
         ftdi_chip_type_t chip_type;
                                 /* type of device, either SIO or FT8U232AM */
         int baud_base;          /* baud base clock for divisor setting */
@@ -669,6 +670,8 @@ static struct usb_device_id id_table_combined [] = {
         { USB_DEVICE(ADI_VID, ADI_GNICE_PID),
                 .driver_info = (kernel_ulong_t)&ftdi_jtag_quirk },
         { USB_DEVICE(JETI_VID, JETI_SPC1201_PID) },
+        { USB_DEVICE(MARVELL_VID, MARVELL_SHEEVAPLUG_PID),
+                .driver_info = (kernel_ulong_t)&ftdi_jtag_quirk },
         { },                                    /* Optional parameter entry */
         { }                                     /* Terminating entry */
 };
@@ -1352,6 +1355,7 @@ static int ftdi_sio_port_probe(struct usb_serial_port *port)
                 return -ENOMEM;
         }
 
+        kref_init(&priv->kref);
         spin_lock_init(&priv->rx_lock);
         spin_lock_init(&priv->tx_lock);
         init_waitqueue_head(&priv->delta_msr_wait);
@@ -1468,6 +1472,13 @@ static void ftdi_shutdown(struct usb_serial *serial)
         dbg("%s", __func__);
 }
 
+static void ftdi_sio_priv_release(struct kref *k)
+{
+        struct ftdi_private *priv = container_of(k, struct ftdi_private, kref);
+
+        kfree(priv);
+}
+
 static int ftdi_sio_port_remove(struct usb_serial_port *port)
 {
         struct ftdi_private *priv = usb_get_serial_port_data(port);
@@ -1476,14 +1487,7 @@ static int ftdi_sio_port_remove(struct usb_serial_port *port)
 
         remove_sysfs_attrs(port);
 
-        /* all open ports are closed at this point
-         *    (by usbserial.c:__serial_close, which calls ftdi_close)
-         */
-
-        if (priv) {
-                usb_set_serial_port_data(port, NULL);
-                kfree(priv);
-        }
+        kref_put(&priv->kref, ftdi_sio_priv_release);
 
         return 0;
 }
@@ -1547,7 +1551,8 @@ static int ftdi_open(struct tty_struct *tty,
                 dev_err(&port->dev,
                         "%s - failed submitting read urb, error %d\n",
                         __func__, result);
-
+        else
+                kref_get(&priv->kref);
 
         return result;
 } /* ftdi_open */
@@ -1589,11 +1594,11 @@ static void ftdi_close(struct tty_struct *tty,
         mutex_unlock(&port->serial->disc_mutex);
 
         /* cancel any scheduled reading */
-        cancel_delayed_work(&priv->rx_work);
-        flush_scheduled_work();
+        cancel_delayed_work_sync(&priv->rx_work);
 
         /* shutdown our bulk read */
         usb_kill_urb(port->read_urb);
+        kref_put(&priv->kref, ftdi_sio_priv_release);
 } /* ftdi_close */
 
 
diff --git a/drivers/usb/serial/ftdi_sio.h b/drivers/usb/serial/ftdi_sio.h
index c09f658a448..12330fa1c09 100644
--- a/drivers/usb/serial/ftdi_sio.h
+++ b/drivers/usb/serial/ftdi_sio.h
@@ -920,6 +920,12 @@
 #define JETI_SPC1201_PID        0x04b2
 
 /*
+ * Marvell SheevaPlug
+ */
+#define MARVELL_VID             0x9e88
+#define MARVELL_SHEEVAPLUG_PID  0x9e8f
+
+/*
  *   BmRequestType:  1100 0000b
  *   bRequest:       FTDI_E2_READ
  *   wValue:         0
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..f331e2bde88 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);
 }
 
@@ -958,6 +974,7 @@ int usb_serial_probe(struct usb_interface *interface,
                 if (retval > 0) {
                         /* quietly accept this device, but don't bind to a
                            serial port as it's about to disappear */
+                        serial->num_ports = 0;
                         goto exit;
                 }
         }
@@ -1043,6 +1060,12 @@ 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 +1075,21 @@ 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,