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Date: Fri, 17 Dec 2010 16:34:23 +0100
From: Libor Pechacek <lpechacek@...e.cz>
To: Alan Cox <alan@...rguk.ukuu.org.uk>,
Greg Kroah-Hartman <gregkh@...e.de>
Cc: Peter Berger <pberger@...mson.com>,
Al Borchers <alborchers@...inerpoint.com>,
linux-usb@...r.kernel.org, linux-kernel@...r.kernel.org
Subject: [PATCH 2.6.36-rc3] USB: serial: handle Data Carrier Detect changes
Alan's commit 335f8514f200e63d689113d29cb7253a5c282967 introduced
.carrier_raised function in several drivers. That also means
tty_port_block_til_ready can now suspend the process trying to open the serial
port when Carrier Detect is low and put it into tty_port.open_wait queue. We
need to wake up the process when the Carrier Detect goes high.
Signed-off-by: Libor Pechacek <lpechacek@...e.cz>
Cc: Greg Kroah-Hartman <gregkh@...e.de>
Cc: Peter Berger <pberger@...mson.com>
Cc: Al Borchers <alborchers@...inerpoint.com>
---
Hi Alan,
This is an amendment of your patch referenced above. Please review and comment
on the changes.
@Greg: There are two drivers left to be fixed - drivers/usb/serial/cp210x.c and
drivers/usb/serial/keyspan_pda.c. cp210x device does not seem to have an
interrupt endpoint to report the changes so a polling thread seems to be needed
to detect DCD changes. I can implement the polling for cp210x if you don't
have a better idea.
The keyspan_pda can report the changes asynchronously, but I haven't found the
message format description anywhere. Any idea how that driver can be fixed
besides dropping .carrier_raised?
drivers/usb/serial/ch341.c | 4 ++++
drivers/usb/serial/digi_acceleport.c | 17 +++++++++++------
drivers/usb/serial/generic.c | 20 ++++++++++++++++++++
drivers/usb/serial/pl2303.c | 4 ++++
drivers/usb/serial/spcp8x5.c | 5 +++++
include/linux/usb/serial.h | 2 ++
6 files changed, 46 insertions(+), 6 deletions(-)
diff --git a/drivers/usb/serial/ch341.c b/drivers/usb/serial/ch341.c
index 63f7cc4..caa1f8d 100644
--- a/drivers/usb/serial/ch341.c
+++ b/drivers/usb/serial/ch341.c
@@ -486,12 +486,16 @@ static void ch341_read_int_callback(struct urb *urb)
if (actual_length >= 4) {
struct ch341_private *priv = usb_get_serial_port_data(port);
unsigned long flags;
+ u8 prev_line_status = priv->line_status;
spin_lock_irqsave(&priv->lock, flags);
priv->line_status = (~(data[2])) & CH341_BITS_MODEM_STAT;
if ((data[1] & CH341_MULT_STAT))
priv->multi_status_change = 1;
spin_unlock_irqrestore(&priv->lock, flags);
+ if ((priv->line_status ^ prev_line_status) & CH341_BIT_DCD)
+ usb_serial_handle_dcd_change(port,
+ priv->line_status & CH341_BIT_DCD);
wake_up_interruptible(&priv->delta_msr_wait);
}
diff --git a/drivers/usb/serial/digi_acceleport.c b/drivers/usb/serial/digi_acceleport.c
index b92070c..396c2c5 100644
--- a/drivers/usb/serial/digi_acceleport.c
+++ b/drivers/usb/serial/digi_acceleport.c
@@ -1738,9 +1738,9 @@ static int digi_read_oob_callback(struct urb *urb)
struct usb_serial *serial = port->serial;
struct tty_struct *tty;
struct digi_port *priv = usb_get_serial_port_data(port);
- int opcode, line, status, val;
+ int opcode, line, status, val, new_dcd_val;
int i;
- unsigned int rts;
+ unsigned int rts, dcd;
dbg("digi_read_oob_callback: port=%d, len=%d",
priv->dp_port_num, urb->actual_length);
@@ -1794,10 +1794,15 @@ static int digi_read_oob_callback(struct urb *urb)
priv->dp_modem_signals |= TIOCM_RI;
else
priv->dp_modem_signals &= ~TIOCM_RI;
- if (val & DIGI_READ_INPUT_SIGNALS_DCD)
- priv->dp_modem_signals |= TIOCM_CD;
- else
- priv->dp_modem_signals &= ~TIOCM_CD;
+
+ dcd = priv->dp_modem_signals & TIOCM_CD;
+ new_dcd_val = val & DIGI_READ_INPUT_SIGNALS_DCD;
+ if (!!new_dcd_val != !!dcd) {
+ priv->dp_modem_signals = new_dcd_val ?
+ priv->dp_modem_signals | TIOCM_CD :
+ priv->dp_modem_signals & ~TIOCM_CD;
+ usb_serial_handle_dcd_change(port, dcd);
+ }
wake_up_interruptible(&priv->dp_modem_change_wait);
spin_unlock(&priv->dp_port_lock);
diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c
index e6833e2..a877767 100644
--- a/drivers/usb/serial/generic.c
+++ b/drivers/usb/serial/generic.c
@@ -479,6 +479,26 @@ int usb_serial_handle_break(struct usb_serial_port *port)
}
EXPORT_SYMBOL_GPL(usb_serial_handle_break);
+/**
+ * usb_serial_handle_dcd_change - handle a change of carrier detect state
+ * @port: usb_serial_port structure for the open port
+ * @status: new carrier detect status, nonzero if active
+ */
+void usb_serial_handle_dcd_change(struct usb_serial_port *usb_port,
+ unsigned int status)
+{
+ struct tty_port *port = &usb_port->port;
+ struct tty_struct *tty = port->tty;
+
+ dbg("%s - port %d, status %d", __func__, usb_port->number, status);
+
+ if (status)
+ wake_up_interruptible(&port->open_wait);
+ else if (tty && !C_CLOCAL(tty))
+ tty_hangup(tty);
+}
+EXPORT_SYMBOL_GPL(usb_serial_handle_dcd_change);
+
int usb_serial_generic_resume(struct usb_serial *serial)
{
struct usb_serial_port *port;
diff --git a/drivers/usb/serial/pl2303.c b/drivers/usb/serial/pl2303.c
index 8ae4c6c..9b4f21b 100644
--- a/drivers/usb/serial/pl2303.c
+++ b/drivers/usb/serial/pl2303.c
@@ -680,6 +680,7 @@ static void pl2303_update_line_status(struct usb_serial_port *port,
unsigned long flags;
u8 status_idx = UART_STATE;
u8 length = UART_STATE + 1;
+ u8 prev_line_status = priv->line_status;
u16 idv, idp;
idv = le16_to_cpu(port->serial->dev->descriptor.idVendor);
@@ -705,6 +706,9 @@ static void pl2303_update_line_status(struct usb_serial_port *port,
spin_unlock_irqrestore(&priv->lock, flags);
if (priv->line_status & UART_BREAK_ERROR)
usb_serial_handle_break(port);
+ if ((priv->line_status ^ prev_line_status) & UART_DCD)
+ usb_serial_handle_dcd_change(port,
+ priv->line_status & UART_DCD);
wake_up_interruptible(&priv->delta_msr_wait);
}
diff --git a/drivers/usb/serial/spcp8x5.c b/drivers/usb/serial/spcp8x5.c
index 765aa98..42bdb6b 100644
--- a/drivers/usb/serial/spcp8x5.c
+++ b/drivers/usb/serial/spcp8x5.c
@@ -452,6 +452,7 @@ static int spcp8x5_open(struct tty_struct *tty, struct usb_serial_port *port)
struct spcp8x5_private *priv = usb_get_serial_port_data(port);
int ret;
unsigned long flags;
+ u8 prev_line_status = priv->line_status;
u8 status = 0x30;
/* status 0x30 means DSR and CTS = 1 other CDC RI and delta = 0 */
@@ -479,6 +480,10 @@ static int spcp8x5_open(struct tty_struct *tty, struct usb_serial_port *port)
priv->line_status = status & 0xf0 ;
spin_unlock_irqrestore(&priv->lock, flags);
+ if ((priv->line_status ^ prev_line_status) & MSR_STATUS_LINE_DCD)
+ usb_serial_handle_dcd_change(port,
+ priv->line_status & MSR_STATUS_LINE_DCD);
+
port->port.drain_delay = 256;
return usb_serial_generic_open(tty, port);
diff --git a/include/linux/usb/serial.h b/include/linux/usb/serial.h
index 16d682f..7fe31a9 100644
--- a/include/linux/usb/serial.h
+++ b/include/linux/usb/serial.h
@@ -347,6 +347,8 @@ extern int usb_serial_generic_prepare_write_buffer(struct usb_serial_port *port,
extern int usb_serial_handle_sysrq_char(struct usb_serial_port *port,
unsigned int ch);
extern int usb_serial_handle_break(struct usb_serial_port *port);
+extern void usb_serial_handle_dcd_change(struct usb_serial_port *usb_port,
+ unsigned int status);
extern int usb_serial_bus_register(struct usb_serial_driver *device);
--
1.6.0.2
--
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