Reset thunderbolt topologies at bootup

Mario Limonciello
2024-04-23T18:54:31Z

Hi,

We've got a collection of bug reports about how if a Thunderbolt device
is connected at bootup it doesn't behave the same as if it were
hotplugged by the user after bootup. Issues range from non-functional
devices or display devices working at lower performance.

All of the issues stem from a pre-OS firmware initializing the USB4
controller and the OS re-using those tunnels. This has been fixed in
6.9-rc1 by resetting the controller to a fresh state and discarding
whatever firmware has done. I'd like to bring it back to 6.6.y LTS and
6.8.y stable.

01da6b99d49f6 thunderbolt: Introduce tb_port_reset()
b35c1d7b11da8 thunderbolt: Introduce tb_path_deactivate_hop()
ec8162b3f0683 thunderbolt: Make tb_switch_reset() support Thunderbolt 2,
3 and USB4 routers
9a54c5f3dbde thunderbolt: Reset topology created by the boot firmware

Thanks!