cc584ab860
After overruns the FIFO pointers become misaligned. This typically shows by characters still being stuck in the FIFO despite the empty flag being asserted. After the first assertion of the overrun flag the empty flag still seems to indicate FIFO state correctly and all data can be read. However, after another overrun assertion the FIFO seems to be off by one such that the last received character is still in the FIFO (despite the empty flag being asserted). Flushing the receive FIFO reinitializes pointers. Hence it is recommended to flush the FIFO after overruns, see also: https://community.nxp.com/thread/321175 Hence, on assertion of the overrun flag read the remaining data from the FIFO and flush buffers. Signed-off-by: Stefan Agner <stefan.agner@toradex.com> Acked-by: Max Krummenacher <max.krummenacher@toradex.com> Cc: Stefan Agner <stefan@agner.ch> Cc: Bhuvanchandra DV <bhuvanchandra.dv@toradex.com> Cc: Chris Healy <cphealy@gmail.com> Cc: Cory Tusar <cory.tusar@zii.aero> Cc: Lucas Stach <l.stach@pengutronix.de> Cc: Greg Kroah-Hartman <gregkh@linuxfoundation.org> Cc: Jiri Slaby <jslaby@suse.com> Cc: linux-imx@nxp.com Cc: linux-serial@vger.kernel.org Cc: linux-kernel@vger.kernel.org Link: https://lore.kernel.org/r/20190729195226.8862-3-andrew.smirnov@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.