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[ Upstream commit8217f07a50] 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: Felipe Balbi <balbi@kernel.org> Signed-off-by: Wesley Cheng <wcheng@codeaurora.org> Link: https://lore.kernel.org/r/20210917021852.2037-1-wcheng@codeaurora.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Stable-dep-of:040f2dbd20("usb: dwc3: gadget: Avoid duplicate requests to enable Run/Stop") Signed-off-by: Sasha Levin <sashal@kernel.org>
Linux kernel
============
There are several guides for kernel developers and users. These guides can
be rendered in a number of formats, like HTML and PDF. Please read
Documentation/admin-guide/README.rst first.
In order to build the documentation, use ``make htmldocs`` or
``make pdfdocs``. The formatted documentation can also be read online at:
https://www.kernel.org/doc/html/latest/
There are various text files in the Documentation/ subdirectory,
several of them using the Restructured Text markup notation.
Please read the Documentation/process/changes.rst file, as it contains the
requirements for building and running the kernel, and information about
the problems which may result by upgrading your kernel.