5f0856bebc
Since NTB connects two physically separate systems, there can be scenarios where one system goes down while the other one remains active. In case of NTB primary, if the NTB secondary goes down, a Link-Down event is received. For the NTB secondary, if the NTB primary goes down, the PCIe hotplug mechanism ensures that the driver on the secondary side is also unloaded. But there are other scenarios to consider as well, when suppose the physical link remains active, but the driver on primary or secondary side is loaded or un-loaded. When the driver is loaded, on either side, it sets SIDE_READY bit(bit-1) of SIDE_INFO register. Similarly, when the driver is un-loaded, it resets the same bit. We consider the NTB link to be up and operational only when the driver on both sides of link are loaded and ready. But we also need to take account of Link Up and Down events which signify the physical link status. So amd_link_is_up() is modified to take care of the above scenarios. Signed-off-by: Arindam Nath <arindam.nath@amd.com> Signed-off-by: Jon Mason <jdmason@kudzu.us>
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.