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Commit 72ec46f5 authored by Anson Jacob's avatar Anson Jacob Committed by Dmitry Shmidt
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ANDROID: usb: gadget: f_accessory: Fix for UsbAccessory clean unbind. 



Reapplying fix by Darren Whobrey (Change 69674)

Fixes issues: 20545, 59667 and 61390.
With prior version of f_accessory.c, UsbAccessories would not
unbind cleanly when application is closed or i/o stopped
while the usb cable is still connected. The accessory gadget
driver would be left in an invalid state which was not reset
on subsequent binding or opening. A reboot was necessary to clear.

In some phones this issues causes the phone to reboot upon
unplugging the USB cable.

Main problem was that acc_disconnect was being called on I/O error
which reset disconnected and online.

Minor fix required to properly track setting and unsetting of
disconnected and online flags. Also added urb Q wakeup's on unbind
to help unblock waiting threads.

Tested on Nexus 7 grouper. Expected behaviour now observed:
closing accessory causes blocked i/o to interrupt with IOException.
Accessory can be restarted following closing of file handle
and re-opening.

This is a generic fix that applies to all devices.

Change-Id: I4e08b326730dd3a2820c863124cee10f7cb5501e
Signed-off-by: default avatarDarren Whobrey <d.whobrey@mildai.org>
Signed-off-by: default avatarAnson Jacob <ansonjacob.aj@gmail.com>
parent a711fa7f

drivers/usb/gadget/function/f_accessory.c

+17 −5
Original line number Diff line number Diff line
@@ -77,9 +77,13 @@ struct acc_dev { 
	struct usb_ep *ep_in;

	struct usb_ep *ep_out;



	/* set to 1 when we connect */

	/* online indicates state of function_set_alt & function_unbind

	 * set to 1 when we connect

	 */

	int online:1;

	/* Set to 1 when we disconnect.



	/* disconnected indicates state of open & release

	 * Set to 1 when we disconnect.

	 * Not cleared until our file is closed.

	 */

	int disconnected:1;
@@ -263,7 +267,6 @@ static struct usb_request *req_get(struct acc_dev *dev, struct list_head *head) 


static void acc_set_disconnected(struct acc_dev *dev)

{

	dev->online = 0;

	dev->disconnected = 1;

}
@@ -763,7 +766,10 @@ static int acc_release(struct inode *ip, struct file *fp) 
	printk(KERN_INFO "acc_release\n");



	WARN_ON(!atomic_xchg(&_acc_dev->open_excl, 0));

	_acc_dev->disconnected = 0;

	/* indicate that we are disconnected

	 * still could be online so don't touch online flag

	 */

	_acc_dev->disconnected = 1;

	return 0;

}
@@ -1011,6 +1017,10 @@ acc_function_unbind(struct usb_configuration *c, struct usb_function *f) 
	struct usb_request *req;

	int i;



	dev->online = 0;		/* clear online flag */

	wake_up(&dev->read_wq);		/* unblock reads on closure */

	wake_up(&dev->write_wq);	/* likewise for writes */



	while ((req = req_get(dev, &dev->tx_idle)))

		acc_request_free(req, dev->ep_in);

	for (i = 0; i < RX_REQ_MAX; i++)
@@ -1142,6 +1152,7 @@ static int acc_function_set_alt(struct usb_function *f, 
	}



	dev->online = 1;

	dev->disconnected = 0; /* if online then not disconnected */



	/* readers may be blocked waiting for us to go online */

	wake_up(&dev->read_wq);
@@ -1154,7 +1165,8 @@ static void acc_function_disable(struct usb_function *f) 
	struct usb_composite_dev	*cdev = dev->cdev;



	DBG(cdev, "acc_function_disable\n");

	acc_set_disconnected(dev);

	acc_set_disconnected(dev); /* this now only sets disconnected */

	dev->online = 0; /* so now need to clear online flag here too */

	usb_ep_disable(dev->ep_in);

	usb_ep_disable(dev->ep_out);