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Input: serio - add hangup support 

The Pulse-Eight USB CEC adapter is a usb device that shows up as a ttyACM0
device.  It requires that you run inputattach in order to communicate with
it via serio.

This all works well, but it would be nice to have a udev rule to
automatically start inputattach. That too works OK, but the problem comes
when the USB device is unplugged: the tty hangup is never handled by the
serio framework so the inputattach utility never exits and you have to kill
it manually.

By adding this hangup callback the inputattach utility now properly exits
as soon as the USB device is unplugged.

The udev rule I used on my Debian sid system is:

SUBSYSTEM=="tty", KERNEL=="ttyACM[0-9]*", ATTRS{idVendor}=="2548", ATTRS{idProduct}=="1002", ACTION=="add", TAG+="systemd", ENV{SYSTEMD_WANTS}+="pulse8-cec-inputattach@%k.service"

And /etc/systemd/system/pulse8-cec-inputattach@.service is as follows:

===============================================================
[Unit]
Description=inputattach for pulse8-cec device on %I

[Service]
Type=simple
ExecStart=/usr/local/bin/inputattach --pulse8-cec /dev/%I
KillMode=process
===============================================================

Signed-off-by: Hans Verkuil <hans.verkuil@cisco.com>
Tested-by: Hans Verkuil <hans.verkuil@cisco.com>
Signed-off-by: Dmitry Torokhov <dmitry.torokhov@gmail.com>
This commit is contained in:
Hans Verkuil 2016-08-04 11:16:23 -07:00 committed by Dmitry Torokhov
parent 722dc54628
commit 51db013767
1 changed files with 14 additions and 3 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

17
drivers/input/serio/serport.c
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@ -71,10 +71,7 @@ static void serport_serio_close(struct serio *serio)
spin_lock_irqsave(&serport->lock, flags);
clear_bit(SERPORT_ACTIVE, &serport->flags);
set_bit(SERPORT_DEAD, &serport->flags);
spin_unlock_irqrestore(&serport->lock, flags);
wake_up_interruptible(&serport->wait);
}
/*
@ -248,6 +245,19 @@ static long serport_ldisc_compat_ioctl(struct tty_struct *tty,
}
#endif
static int serport_ldisc_hangup(struct tty_struct *tty)
{
struct serport *serport = (struct serport *) tty->disc_data;
unsigned long flags;
spin_lock_irqsave(&serport->lock, flags);
set_bit(SERPORT_DEAD, &serport->flags);
spin_unlock_irqrestore(&serport->lock, flags);
wake_up_interruptible(&serport->wait);
return 0;
}
static void serport_ldisc_write_wakeup(struct tty_struct * tty)
{
struct serport *serport = (struct serport *) tty->disc_data;
@ -274,6 +284,7 @@ static struct tty_ldisc_ops serport_ldisc = {
.compat_ioctl = serport_ldisc_compat_ioctl,
#endif
.receive_buf = serport_ldisc_receive,
.hangup = serport_ldisc_hangup,
.write_wakeup = serport_ldisc_write_wakeup
};