This removes tty->low_latency from all USB serial drivers that pushdata into the tty layer at hard interrupt context. It's no longer neededand 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 4875efd2c38ae77994c488d13d0ce1f900921d1bAuthor: 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.cindex 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.cindex 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.cindex 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.cindex 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.cindex 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.cindex 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.cindex 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.cindex 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.cindex 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.cindex 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.cindex 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.cindex 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.cindex 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.cindex 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.cindex 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.cindex 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.cindex 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.cindex 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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