Return-Path: Received: (majordomo@vger.kernel.org) by vger.kernel.org via listexpand id S1755443Ab0LQPe7 (ORCPT ); Fri, 17 Dec 2010 10:34:59 -0500 Received: from cantor.suse.de ([195.135.220.2]:33990 "EHLO mx1.suse.de" rhost-flags-OK-OK-OK-OK) by vger.kernel.org with ESMTP id S1755381Ab0LQPey (ORCPT ); Fri, 17 Dec 2010 10:34:54 -0500 Date: Fri, 17 Dec 2010 16:34:23 +0100 From: Libor Pechacek To: Alan Cox , Greg Kroah-Hartman Cc: Peter Berger , Al Borchers , linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org Subject: [PATCH 2.6.36-rc3] USB: serial: handle Data Carrier Detect changes Message-ID: <20101217153422.GE20400@fm.suse.cz> MIME-Version: 1.0 Content-Type: text/plain; charset=us-ascii Content-Disposition: inline User-Agent: Mutt/1.5.18-muttng (2008-05-17-r1399) Sender: linux-kernel-owner@vger.kernel.org List-ID: X-Mailing-List: linux-kernel@vger.kernel.org Content-Length: 7375 Lines: 188 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 Cc: Greg Kroah-Hartman Cc: Peter Berger Cc: Al Borchers --- 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 -- To unsubscribe from this list: send the line "unsubscribe linux-kernel" in the body of a message to majordomo@vger.kernel.org More majordomo info at http://vger.kernel.org/majordomo-info.html Please read the FAQ at http://www.tux.org/lkml/