On Wed, Dec 13, 2023 at 12:46:35AM +0530, Sanath S wrote:
> Boot firmware might have created tunnels of its own. Since we cannot
> be sure they are usable for us. Tear them down and reset the ports
> to handle it as a new hotplug for USB3 routers.
>
> Suggested-by: Mario Limonciello <mario.limonciello@xxxxxxx>
> Signed-off-by: Sanath S <Sanath.S@xxxxxxx>
> ---
> drivers/thunderbolt/tb.c | 11 +++++++++++
> 1 file changed, 11 insertions(+)
>
> diff --git a/drivers/thunderbolt/tb.c b/drivers/thunderbolt/tb.c
> index fd49f86e0353..febd0b6972e3 100644
> --- a/drivers/thunderbolt/tb.c
> +++ b/drivers/thunderbolt/tb.c
> @@ -2598,6 +2598,17 @@ static int tb_start(struct tb *tb)
> tb_switch_tmu_enable(tb->root_switch);
> /* Full scan to discover devices added before the driver was loaded. */
> tb_scan_switch(tb->root_switch);
> + /*
> + * Boot firmware might have created tunnels of its own. Since we cannot
> + * be sure they are usable for us, Tear them down and reset the ports
> + * to handle it as new hotplug for USB4 routers.
> + */
> + if (tb_switch_is_usb4(tb->root_switch)) {
> + tb_switch_discover_tunnels(tb->root_switch,
> + &tcm->tunnel_list, false);
Why this is needed?
It should be enough, to do simply something like this:
if (tb_switch_is_usb4(tb->root_switch))
tb_switch_reset(tb->root_switch);
and continue with the rest of the function. The tb_switch_reset() then
resets the downstream ports synchronously so when it returns there is
nothing to be discover.
(We can use the tb_switch_reset() here, it already exists and is
performing TBT 1 specific things but you can make it handle downstream
port reset in case of USB4).
You don't need to touch the ->hotplug_active or anything else here.
> + tcm->hotplug_active = true;
> + return tb_switch_reset_ports(tb->root_switch);
> + }
> /* Find out tunnels created by the boot firmware */
> tb_discover_tunnels(tb);
> /* Add DP resources from the DP tunnels created by the boot firmware */
> --
> 2.34.1
