29940ce32a
DSA inherits NETIF_F_CSUM_MASK from master->vlan_features, and the expectation is that TX checksumming is offloaded and not done in software. Normally the DSA master takes care of this, but packets handled by ocelot_defer_xmit() are a very special exception, because they are actually injected into the switch through register-based MMIO. So the DSA master is not involved at all for these packets => no one calculates the checksum. This allows PTP over UDP to work using the ocelot-8021q tagging protocol. Signed-off-by: Vladimir Oltean <vladimir.oltean@nxp.com> Signed-off-by: David S. Miller <davem@davemloft.net>
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.