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commit 59a54c5f3dbde00b8ad30aef27fe35b1fe07bf5c upstream. Boot firmware (typically BIOS) might have created tunnels of its own. The tunnel configuration that it does might be sub-optimal. For instance it may only support HBR2 monitors so the DisplayPort tunnels it created may limit Linux graphics drivers. In addition there is an issue on some AMD based systems where the BIOS does not allocate enough PCIe resources for future topology extension. By resetting the USB4 topology the PCIe links will be reset as well allowing Linux to re-allocate. This aligns the behavior with Windows Connection Manager. We already issued host router reset for USB4 v2 routers, now extend it to USB4 v1 routers as well. For pre-USB4 (that's Apple systems) we leave it as is and continue to discover the existing tunnels. Suggested-by: Mario Limonciello <mario.limonciello@amd.com> Signed-off-by: Sanath S <Sanath.S@amd.com> Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.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.