When flow control is enabled, the UART should set RTS to false during suspend to stop incoming data. Currently, the suspend routine sets the mctrl register in the uart to zero, but leaves the shadow version in the uart_port struct alone so that resume can restore it. This causes a problem later in suspend when serial8250_do_shutdown() is called which uses the shadow mctrl register to clear some additional bits but ends up restoring RTS. The solution is to clear RTS from the shadow version before serial8250_do_shutdown() is called and restore it after. Signed-off-by: Al Cooper <alcooperx@comcast.net> Link: https://lore.kernel.org/r/20220324145620.41573-1-alcooperx@gmail.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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