On Fri, 23 Mar 2012, Johan Hovold wrote:
> I'm afraid I don't have time to debug this further today, but I did a
> quick test removing the if statement above. It didn't oops at unload,
> but instead I got the following warning when the module was reloaded:
>
>
> [ 291.257618] drivers/usb/serial/usb-serial.c: usb_serial_probe - registering ttyUSB0
> [ 291.257830] ------------[ cut here ]------------
> [ 291.257854] WARNING: at fs/sysfs/dir.c:481 sysfs_add_one+0x95/0xd0()
> [ 291.257883] Hardware name: Vostro 1520
> [ 291.257893] sysfs: cannot create duplicate filename '/dev/char/188:0'
Here's a patch for you to try. On my system I don't get any warnings
or errors while using it with a PL2303.
I no longer remember clearly why I added all that stuff to keep track
of the port's registration state. Maybe I was concerned about what
would happen if someone used sysfs to unbind a port from its driver.
For most of the serial drivers this wouldn't have any effect, because
they don't implement the port_probe and port_remove methods.
Alan Stern
drivers/usb/serial/bus.c | 5 -----
drivers/usb/serial/usb-serial.c | 23 ++---------------------
include/linux/usb/serial.h | 8 --------
3 files changed, 2 insertions(+), 34 deletions(-)
Index: usb-3.3/include/linux/usb/serial.h
===================================================================
--- usb-3.3.orig/include/linux/usb/serial.h
+++ usb-3.3/include/linux/usb/serial.h
@@ -28,13 +28,6 @@
/* parity check flag */
#define RELEVANT_IFLAG(iflag) (iflag & (IGNBRK|BRKINT|IGNPAR|PARMRK|INPCK))
-enum port_dev_state {
- PORT_UNREGISTERED,
- PORT_REGISTERING,
- PORT_REGISTERED,
- PORT_UNREGISTERING,
-};
-
/* USB serial flags */
#define USB_SERIAL_WRITE_BUSY 0
@@ -124,7 +117,6 @@ struct usb_serial_port {
char throttle_req;
unsigned long sysrq; /* sysrq timeout */
struct device dev;
- enum port_dev_state dev_state;
};
#define to_usb_serial_port(d) container_of(d, struct usb_serial_port, dev)
Index: usb-3.3/drivers/usb/serial/usb-serial.c
===================================================================
--- usb-3.3.orig/drivers/usb/serial/usb-serial.c
+++ usb-3.3/drivers/usb/serial/usb-serial.c
@@ -1074,17 +1074,12 @@ int usb_serial_probe(struct usb_interfac
port = serial->port[i];
dev_set_name(&port->dev, "ttyUSB%d", port->number);
dbg ("%s - registering %s", __func__, dev_name(&port->dev));
- port->dev_state = PORT_REGISTERING;
device_enable_async_suspend(&port->dev);
retval = device_add(&port->dev);
- if (retval) {
+ if (retval)
dev_err(&port->dev, "Error registering port device, "
"continuing\n");
- port->dev_state = PORT_UNREGISTERED;
- } else {
- port->dev_state = PORT_REGISTERED;
- }
}
usb_serial_console_init(debug, minor);
@@ -1128,22 +1123,8 @@ void usb_serial_disconnect(struct usb_in
}
kill_traffic(port);
cancel_work_sync(&port->work);
- if (port->dev_state == PORT_REGISTERED) {
-
- /* Make sure the port is bound so that the
- * driver's port_remove method is called.
- */
- if (!port->dev.driver) {
- int rc;
-
- port->dev.driver =
- &serial->type->driver;
- rc = device_bind_driver(&port->dev);
- }
- port->dev_state = PORT_UNREGISTERING;
+ if (device_is_registered(&port->dev))
device_del(&port->dev);
- port->dev_state = PORT_UNREGISTERED;
- }
}
}
serial->type->disconnect(serial);
Index: usb-3.3/drivers/usb/serial/bus.c
===================================================================
--- usb-3.3.orig/drivers/usb/serial/bus.c
+++ usb-3.3/drivers/usb/serial/bus.c
@@ -60,8 +60,6 @@ static int usb_serial_device_probe(struc
retval = -ENODEV;
goto exit;
}
- if (port->dev_state != PORT_REGISTERING)
- goto exit;
driver = port->serial->type;
if (driver->port_probe) {
@@ -98,9 +96,6 @@ static int usb_serial_device_remove(stru
if (!port)
return -ENODEV;
- if (port->dev_state != PORT_UNREGISTERING)
- return retval;
-
device_remove_file(&port->dev, &dev_attr_port_number);
driver = port->serial->type;
--
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