This is a note to let you know that I've just added the patch titled
USB: cdc-acm: fix device unregistration
to my usb git tree which can be found at
git://git.kernel.org/pub/scm/linux/kernel/git/gregkh/usb.git
in the usb-linus branch.
The patch will show up in the next release of the linux-next tree
(usually sometime within the next 24 hours during the week.)
The patch will hopefully also be merged in Linus's tree for the
next -rc kernel release.
If you have any questions about this process, please let me know.
>From cb25505fc604292c70fc02143fc102f54c8595f0 Mon Sep 17 00:00:00 2001
From: Johan Hovold <jhovold@xxxxxxxxx>
Date: Tue, 19 Mar 2013 09:21:06 +0100
Subject: USB: cdc-acm: fix device unregistration
Unregister tty device in disconnect as is required by the USB stack.
By deferring unregistration to when the last tty reference is dropped,
the parent interface device can get unregistered before the child
resulting in broken hotplug events being generated when the tty is
finally closed:
KERNEL[2290.798128] remove /devices/pci0000:00/0000:00:1d.7/usb2/2-1/2-1:3.1 (usb)
KERNEL[2290.804589] remove /devices/pci0000:00/0000:00:1d.7/usb2/2-1 (usb)
KERNEL[2294.554799] remove /2-1:3.1/tty/ttyACM0 (tty)
The driver must deal with tty callbacks after disconnect by checking the
disconnected flag. Specifically, further opens must be prevented and
this is already implemented.
Cc: stable <stable@xxxxxxxxxxxxxxx>
Cc: Oliver Neukum <oneukum@xxxxxxx>
Acked-by: Oliver Neukum <oneukum@xxxxxxx>
Signed-off-by: Johan Hovold <jhovold@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/class/cdc-acm.c | 3 ++-
1 file changed, 2 insertions(+), 1 deletion(-)
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index c125b61..387dc6c 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -593,7 +593,6 @@ static void acm_port_destruct(struct tty_port *port)
dev_dbg(&acm->control->dev, "%s\n", __func__);
- tty_unregister_device(acm_tty_driver, acm->minor);
acm_release_minor(acm);
usb_put_intf(acm->control);
kfree(acm->country_codes);
@@ -1426,6 +1425,8 @@ static void acm_disconnect(struct usb_interface *intf)
stop_data_traffic(acm);
+ tty_unregister_device(acm_tty_driver, acm->minor);
+
usb_free_urb(acm->ctrlurb);
for (i = 0; i < ACM_NW; i++)
usb_free_urb(acm->wb[i].urb);
--
1.8.0.rc0.18.gf84667d
--
To unsubscribe from this list: send the line "unsubscribe stable" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html