[05/26] usb: musb: fix oops on musb_gadget_pullup

From: Greg KH
Date: Mon Aug 15 2011 - 22:53:32 EST

3.0-stable review patch. If anyone has any objections, please let us know.


From: John Stultz <john.stultz@xxxxxxxxxx>

commit 72c487dfb94d02025fb7437dfe2314d836d5a9ab upstream.

an 'unhandled fault' is causes when a gadget driver calls
usb_gadget_connect() while the USB cable isn't plugged into
the OTG port.

the fault is caused by an access to MUSB's memory space
while its clock is turned off due to pm_runtime kicking

in order to fix the fault, we enclose musb_gadget_pullup()
with pm_runtime_get_sync() ... pm_runtime_put() calls to
be sure we will always reach that path with clock turned on.

[ balbi@xxxxxx : simplified commit log; removed few things
which didn't belong there ]

Reported-by: Zach Pfeffer <zach.pfeffer@xxxxxxxxxx>
Signed-off-by: John Stultz <john.stultz@xxxxxxxxxx>
Signed-off-by: Felipe Balbi <balbi@xxxxxx>
Signed-off-by: Greg Kroah-Hartman <gregkh@xxxxxxx>

drivers/usb/musb/musb_gadget.c | 5 +++++
1 file changed, 5 insertions(+)

--- a/drivers/usb/musb/musb_gadget.c
+++ b/drivers/usb/musb/musb_gadget.c
@@ -1698,6 +1698,8 @@ static int musb_gadget_pullup(struct usb

is_on = !!is_on;

+ pm_runtime_get_sync(musb->controller);
/* NOTE: this assumes we are sensing vbus; we'd rather
* not pullup unless the B-session is active.
@@ -1707,6 +1709,9 @@ static int musb_gadget_pullup(struct usb
musb_pullup(musb, is_on);
spin_unlock_irqrestore(&musb->lock, flags);
+ pm_runtime_put(musb->controller);
return 0;

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