This removes tty->low_latency from all USB serial drivers that push
data into the tty layer at hard interrupt context. It's no longer needed
and actually harmful.
Signed-off-by: Oliver Neukum <oliver@xxxxxxxxxx>
As this is a genuine bug fix, I am sending it separately. Alan,
should this go into the stable series, too?
Regards
Oliver
commit 4875efd2c38ae77994c488d13d0ce1f900921d1b
Author: Oliver Neukum <oneukum@xxxxxxxxxxxxxxx>
Date: Tue Apr 14 16:46:32 2009 +0200
remove the old tty->low_latency hack in drivers pushing data into the tty
layer
in hard interrupt context
diff --git a/drivers/usb/serial/cyberjack.c b/drivers/usb/serial/cyberjack.c
index 858bdd0..dd501bb 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 eae4740..e568710 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 8a69cce..c709ec4 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 a26a0e2..586d30f 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 9d57cac..4cec990 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 e85c8c0..fb4a73d 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 c3cdd00..513b25e 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 ef92095..cd62825 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 f530032..da2a2b4 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 2314c6a..4473d44 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 6286baa..c148544 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 e772cc0..24e3b5d 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 2c20e88..10f01a6 100644
--- a/drivers/usb/serial/mos7840.c
+++ b/drivers/usb/serial/mos7840.c
@@ -1000,12 +1000,6 @@ 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.) */
diff --git a/drivers/usb/serial/opticon.c b/drivers/usb/serial/opticon.c
index 839583d..b500ad1 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 d560c0b..921694b 100644
--- a/drivers/usb/serial/option.c
+++ b/drivers/usb/serial/option.c
@@ -931,9 +931,6 @@ 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 d9bf9a5..22a46a6 100644
--- a/drivers/usb/serial/sierra.c
+++ b/drivers/usb/serial/sierra.c
@@ -585,9 +585,6 @@ 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 2620bf6..b3ee50f 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));
@@ -1452,7 +1441,6 @@ 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/visor.c b/drivers/usb/serial/visor.c
index 4facce3..5ac414b 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,
--
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