On Wed, Dec 13, 2023 at 07:49:14AM +0200, Mika Westerberg wrote:
> 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);
Actually this needs to be done only for USB4 v1 routers since we already
reset USB4 v2 hosts so something like:
/*
* Reset USB4 v1 host router to get rid of possible tunnels the
* boot firmware created. This makes sure all the tunnels are
* created by us and thus have known configuration.
*
* For USB4 v2 and beyond we do this in nhi_reset() using the
* host router reset interface.
*/
if (usb4_switch_version(tb->root_switch) == 1)
tb_switch_reset(tb->root_switch);
(possibly add similar comment to the nhi_reset() to refer this one).
