[ 43/61] usb: cdc-acm: fix devices not unthrottled on open

From: Greg KH
Date: Wed Jun 20 2012 - 14:23:07 EST


3.4-stable review patch. If anyone has any objections, please let me know.

------------------

From: Otto Meta <otto.patches@xxxxxxxxxxxxxxxx>

commit 6c4707f3f8c44ec18282e1c014c80e1c257042f9 upstream.

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@xxxxxxxxxxxxxxxx>
Acked-by: Johan Hovold <jhovold@xxxxxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxxxxxxxxxxxxxx>

---
drivers/usb/class/cdc-acm.c | 8 ++++++++
1 file changed, 8 insertions(+)

--- a/drivers/usb/class/cdc-acm.c
+++ b/drivers/usb/class/cdc-acm.c
@@ -567,6 +567,14 @@ static int acm_port_activate(struct tty_

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;



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