usb: dwc3: gadget: Avoid starting DWC3 gadget during UDC unbind
There is a race present where the DWC3 runtime resume runs in parallel to the UDC unbind sequence. This will eventually lead to a possible scenario where we are enabling the run/stop bit, without a valid composition defined. Thread#1 (handling UDC unbind): usb_gadget_remove_driver() -->usb_gadget_disconnect() -->dwc3_gadget_pullup(0) --> continue UDC unbind sequence -->Thread#2 is running in parallel here Thread#2 (handing next cable connect) __dwc3_set_mode() -->pm_runtime_get_sync() -->dwc3_gadget_resume() -->dwc->gadget_driver is NOT NULL yet -->dwc3_gadget_run_stop(1) --> _dwc3gadget_start() ... Fix this by tracking the pullup disable routine, and avoiding resuming of the DWC3 gadget. Once the UDC is re-binded, that will trigger the pullup enable routine, which would handle enabling the DWC3 gadget. Acked-by: NFelipe Balbi <balbi@kernel.org> Signed-off-by: NWesley Cheng <wcheng@codeaurora.org> Link: https://lore.kernel.org/r/20210917021852.2037-1-wcheng@codeaurora.orgSigned-off-by: NGreg Kroah-Hartman <gregkh@linuxfoundation.org>
Showing
想要评论请 注册 或 登录