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usb: musb: fix oops on musb_gadget_pullup 

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.

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@ti.com : simplified commit log; removed few things
	which didn't belong there ]

Cc: stable@kernel.org
Reported-by: Zach Pfeffer <zach.pfeffer@linaro.org>
Signed-off-by: John Stultz <john.stultz@linaro.org>
Signed-off-by: Felipe Balbi <balbi@ti.com>
This commit is contained in:
John Stultz 2011-07-20 17:09:34 -07:00 committed by Felipe Balbi
parent d4aefec5da
commit 72c487dfb9
1 changed files with 5 additions and 0 deletions
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5
drivers/usb/musb/musb_gadget.c
View File

@ -1698,6 +1698,8 @@ static int musb_gadget_pullup(struct usb_gadget *gadget, int is_on)
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_gadget *gadget, int is_on)
musb_pullup(musb, is_on);
}
spin_unlock_irqrestore(&musb->lock, flags);
pm_runtime_put(musb->controller);
return 0;
}