From: Denis Joseph Barrow <D.Barow@option.com>
To: Linux Serial <linux-serial@vger.kernel.org>,
Linux USB kernel mailing list <linux-usb@vger.kernel.org>,
Linux netdev Mailing list <netdev@vger.kernel.org>
Subject: [PATCH] hso set tty->low_latency to 0
Date: Mon, 19 Jan 2009 16:46:59 +0100 [thread overview]
Message-ID: <4974A073.3060102@option.com> (raw)
[-- Attachment #1: Type: text/plain, Size: 3624 bytes --]
Hi all,
Alan Cox wanted low_latency set to 0,
this I believe does the job & throttling & unthrottling.
Let me know if there are any problems.
Sets tty->low_latency to 0 gets rid of the unthrottle
tasklet which is no longer neccessary with low_latency=0
& infinite loops which would manifest themselves in
put_rxbuf_data as a result of setting low_latency to 0.
Signed-off-by: Denis Joseph Barrow <D.Barow@option.com>
---
Index: linux-2.6/drivers/net/usb/hso.c
===================================================================
--- linux-2.6.orig/drivers/net/usb/hso.c 2009-01-19 16:30:59.000000000 +0100
+++ linux-2.6/drivers/net/usb/hso.c 2009-01-19 16:31:20.000000000 +0100
@@ -269,7 +269,6 @@
int curr_rx_urb_idx;
u16 curr_rx_urb_offset;
u8 rx_urb_filled[MAX_RX_URBS];
- struct tasklet_struct unthrottle_tasklet;
};
struct hso_device {
@@ -1240,27 +1239,17 @@
}
}
-/*
- * This needs to be a tasklet otherwise we will
- * end up recursively calling this function.
- */
-void hso_unthrottle_tasklet(struct hso_serial *serial)
+
+static void hso_unthrottle(struct tty_struct *tty)
{
- unsigned long flags;
+ struct hso_serial *serial = get_serial_by_tty(tty);
- spin_lock_irqsave(&serial->serial_lock, flags);
+ spin_lock_irq(&serial->serial_lock);
if ((serial->parent->port_spec & HSO_INTF_MUX))
put_rxbuf_data_and_resubmit_ctrl_urb(serial);
else
put_rxbuf_data_and_resubmit_bulk_urb(serial);
- spin_unlock_irqrestore(&serial->serial_lock, flags);
-}
-
-static void hso_unthrottle(struct tty_struct *tty)
-{
- struct hso_serial *serial = get_serial_by_tty(tty);
-
- tasklet_hi_schedule(&serial->unthrottle_tasklet);
+ spin_unlock_irq(&serial->serial_lock);
}
/* open the requested serial port */
@@ -1295,13 +1284,9 @@
/* check for port already opened, if not set the termios */
serial->open_count++;
if (serial->open_count == 1) {
- tty->low_latency = 1;
serial->rx_state = RX_IDLE;
/* Force default termio settings */
_hso_serial_set_termios(tty, NULL);
- tasklet_init(&serial->unthrottle_tasklet,
- (void (*)(unsigned long))hso_unthrottle_tasklet,
- (unsigned long)serial);
result = hso_start_serial_device(serial->parent, GFP_KERNEL);
if (result) {
hso_stop_serial_device(serial->parent);
@@ -1355,7 +1340,6 @@
spin_unlock_irq(&serial->serial_lock);
if (!usb_gone)
hso_stop_serial_device(serial->parent);
- tasklet_kill(&serial->unthrottle_tasklet);
}
if (!usb_gone)
@@ -1885,12 +1869,11 @@
if (serial->rx_state == RX_IDLE) {
/* Setup and send a ctrl req read on
* port i */
- if (!serial->rx_urb_filled[0]) {
+ if (!serial->rx_urb_filled[0]) {
serial->rx_state = RX_SENT;
hso_mux_serial_read(serial);
} else
serial->rx_state = RX_PENDING;
-
} else {
D1("Already pending a read on "
"port %d\n", i);
@@ -2048,6 +2031,15 @@
(tty, urb->transfer_buffer +
serial->curr_rx_urb_offset,
write_length_remaining);
+ if (curr_write_len == 0) {
+ /* Setting TTY_THROTTLED is ugly but
+ we need a the hso_unthrottle callback
+ to say we can start resubmitting URBS.
+ */
+ set_bit(TTY_THROTTLED, &tty->flags);
+ tty_kref_put(tty);
+ return -1;
+ }
serial->curr_rx_urb_offset += curr_write_len;
write_length_remaining -= curr_write_len;
tty_flip_buffer_push(tty);
--
best regards,
D.J. Barrow
Linux Kernel Developer
Option NV, Gaston Geenslaan 14, 3001 Leuven, Belgium
T: +32 16 311 621
F: +32 16 207 164
d.barow@option.com
www.option.com
Disclaimer:
http://www.option.com/company/disclaimer.shtml
[-- Attachment #2: hso_low_latency_fix.patch --]
[-- Type: text/x-diff, Size: 3241 bytes --]
Sets tty->low_latency to 0 gets rid of the unthrottle
tasklet which is no longer neccessary with low_latency=0
& infinite loops which would manifest themselves in
put_rxbuf_data as a result of setting low_latency to 0.
Signed-off-by: Denis Joseph Barrow <D.Barow@option.com>
---
Index: linux-2.6/drivers/net/usb/hso.c
===================================================================
--- linux-2.6.orig/drivers/net/usb/hso.c 2009-01-19 16:30:59.000000000 +0100
+++ linux-2.6/drivers/net/usb/hso.c 2009-01-19 16:31:20.000000000 +0100
@@ -269,7 +269,6 @@
int curr_rx_urb_idx;
u16 curr_rx_urb_offset;
u8 rx_urb_filled[MAX_RX_URBS];
- struct tasklet_struct unthrottle_tasklet;
};
struct hso_device {
@@ -1240,27 +1239,17 @@
}
}
-/*
- * This needs to be a tasklet otherwise we will
- * end up recursively calling this function.
- */
-void hso_unthrottle_tasklet(struct hso_serial *serial)
+
+static void hso_unthrottle(struct tty_struct *tty)
{
- unsigned long flags;
+ struct hso_serial *serial = get_serial_by_tty(tty);
- spin_lock_irqsave(&serial->serial_lock, flags);
+ spin_lock_irq(&serial->serial_lock);
if ((serial->parent->port_spec & HSO_INTF_MUX))
put_rxbuf_data_and_resubmit_ctrl_urb(serial);
else
put_rxbuf_data_and_resubmit_bulk_urb(serial);
- spin_unlock_irqrestore(&serial->serial_lock, flags);
-}
-
-static void hso_unthrottle(struct tty_struct *tty)
-{
- struct hso_serial *serial = get_serial_by_tty(tty);
-
- tasklet_hi_schedule(&serial->unthrottle_tasklet);
+ spin_unlock_irq(&serial->serial_lock);
}
/* open the requested serial port */
@@ -1295,13 +1284,9 @@
/* check for port already opened, if not set the termios */
serial->open_count++;
if (serial->open_count == 1) {
- tty->low_latency = 1;
serial->rx_state = RX_IDLE;
/* Force default termio settings */
_hso_serial_set_termios(tty, NULL);
- tasklet_init(&serial->unthrottle_tasklet,
- (void (*)(unsigned long))hso_unthrottle_tasklet,
- (unsigned long)serial);
result = hso_start_serial_device(serial->parent, GFP_KERNEL);
if (result) {
hso_stop_serial_device(serial->parent);
@@ -1355,7 +1340,6 @@
spin_unlock_irq(&serial->serial_lock);
if (!usb_gone)
hso_stop_serial_device(serial->parent);
- tasklet_kill(&serial->unthrottle_tasklet);
}
if (!usb_gone)
@@ -1885,12 +1869,11 @@
if (serial->rx_state == RX_IDLE) {
/* Setup and send a ctrl req read on
* port i */
- if (!serial->rx_urb_filled[0]) {
+ if (!serial->rx_urb_filled[0]) {
serial->rx_state = RX_SENT;
hso_mux_serial_read(serial);
} else
serial->rx_state = RX_PENDING;
-
} else {
D1("Already pending a read on "
"port %d\n", i);
@@ -2048,6 +2031,15 @@
(tty, urb->transfer_buffer +
serial->curr_rx_urb_offset,
write_length_remaining);
+ if (curr_write_len == 0) {
+ /* Setting TTY_THROTTLED is ugly but
+ we need a the hso_unthrottle callback
+ to say we can start resubmitting URBS.
+ */
+ set_bit(TTY_THROTTLED, &tty->flags);
+ tty_kref_put(tty);
+ return -1;
+ }
serial->curr_rx_urb_offset += curr_write_len;
write_length_remaining -= curr_write_len;
tty_flip_buffer_push(tty);
reply other threads:[~2009-01-19 15:47 UTC|newest]
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