Root-cause: There is an issue like endpoint is not recognized as primed, when bus have more pressure and the add dTD tripwire semaphore (ATDTW bit in USBCMD register) that can cause the controller to ignore a dTD that is added to a primed endpoint. This issue observed with the Windows10 host machine. Workaround: The software must implement a periodic cycle, and check for each dTD, if the endpoint is primed. It can do this by reading the corresponding bits in the ENDPTPRIME and ENDPTSTAT registers. If these bits are read at 0, the software needs to re-prime the endpoint by writing 1 to the corresponding bit in the ENDPTPRIME register. Added conditional revision check of 2.20[CI_REVISION_22]. Link: https://lore.kernel.org/linux-usb/SJ0PR02MB8644CBBA848A0F68323F1AA5D4D99@SJ0PR02MB8644.namprd02.prod.outlook.com/ Acked-by: Peter Chen <peter.chen@kernel.org> Signed-off-by: Piyush Mehta <piyush.mehta@xilinx.com> Link: https://lore.kernel.org/r/20210913140005.955699-1-piyush.mehta@xilinx.com Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.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.
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