usb: cdc-acm: fix devices not unthrottled on open
Currently CDC-ACM devices stay throttled when their TTY is closed while
throttled, stalling further communication attempts after the next open.
Unthrottling during open/activate got lost starting with kernel
3.0.0 and this patch reintroduces it.
Signed-off-by: Otto Meta <otto.patches@sister-shadow.de>
Cc: stable <stable@vger.kernel.org>
Acked-by: Johan Hovold <jhovold@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
diff --git a/drivers/usb/class/cdc-acm.c b/drivers/usb/class/cdc-acm.c
index f2a120e..36a2a0b 100644
--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -567,6 +567,14 @@
usb_autopm_put_interface(acm->control);
+ /*
+ * Unthrottle device in case the TTY was closed while throttled.
+ */
+ spin_lock_irq(&acm->read_lock);
+ acm->throttled = 0;
+ acm->throttle_req = 0;
+ spin_unlock_irq(&acm->read_lock);
+
if (acm_submit_read_urbs(acm, GFP_KERNEL))
goto error_submit_read_urbs;