Comment 0 for bug 2058333

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.

Fixes merged to linus tree for v6.9-rc1:
* 59a54c5f3dbde thunderbolt: Reset topology created by the boot firmware
* ec8162b3f0683 thunderbolt: Make tb_switch_reset() support Thunderbolt 2, 3 and USB4 routers
* b35c1d7b11da8 thunderbolt: Introduce tb_path_deactivate_hop()
* 01da6b99d49f6 thunderbolt: Introduce tb_port_reset()