8afe909b78
To perform proper Display Port tunneling for Thunderbolt 3 devices we need to allocate DP resources for DP IN port before they can be used. The reason for this is that the user can also connect a monitor directly to the Type-C ports in which case the Thunderbolt controller acts as re-driver for Display Port (no tunneling takes place) taking the DP sinks away from the connection manager. This allocation is done using special sink allocation registers available through the link controller. We can pair DP IN to DP OUT only if * DP IN has sink allocated via link controller * DP OUT port receives hotplug event For DP IN adapters (only for the host router) we first query whether there is DP resource available (it may be the previous instance of the driver for example already allocated it) and if it is we add it to the list. We then update the list when after each plug/unplug event to a DP IN/OUT adapter. Each time the list is updated we try to find additional DP IN <-> DP OUT pairs for tunnel establishment. This strategy also makes it possible to establish another tunnel in case there are 3 monitors connected and one gets unplugged releasing the DP IN adapter for the new tunnel. Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
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.