Re: [PATCH v2 2/7] thunderbolt: Make the DP tunnel activation callback mandatory

[Sven Peter]

On 8/24/26 12:45, Mika Westerberg wrote:
> On Sun, Aug 23, 2026 at 06:09:15PM +0200, Sven Peter wrote:
> > tb_tunnel_alloc_dp() takes an optional callback which is run from
> > dprx_work once the DPRX capabilities read has completed. Without that
> > callback tb_dp_dprx_start() reads the capabilities synchronously and
> > never queues the work. It however always takes a tunnel reference which
> > is only dropped by dprx_work itself or by tb_dp_dprx_stop() when
> > cancel_delayed_work() actually canceled that work. That reference is
> > thus leaked for every tunnel without a callback.
> >
> > The only tunnels without one are those from tb_tunnel_discover_dp(),
> > which are activated again when restoring from hibernation.
> > Pass the callback to tb_tunnel_discover_dp() as well and drop the
> > synchronous path such that the DPRX capabilities are always read from
> > dprx_work. Hibernation restore then also no longer blocks for up to 12
> > seconds while waiting for that read to complete.
> >
> > Also fix up the KUnit tests.
> >
> > Fixes: d6d458d42e1e ("thunderbolt: Handle DisplayPort tunnel activation asynchronously")
> > Cc: stable@xxxxxxxxxxxxxxx
> > Signed-off-by: Sven Peter <sven@xxxxxxxxxx>
> > ---
> >   drivers/thunderbolt/tb.c     |  4 +++-
> >   drivers/thunderbolt/test.c   | 37 +++++++++++++++++++++++-----------
> >   drivers/thunderbolt/tunnel.c | 47 ++++++++++++++++++++++++--------------------
> >   drivers/thunderbolt/tunnel.h |  8 +++++---
> >   4 files changed, 60 insertions(+), 36 deletions(-)
> >
> > diff --git a/drivers/thunderbolt/tb.c b/drivers/thunderbolt/tb.c
> > index f43f2d952372..29b9879c40d8 100644
> > --- a/drivers/thunderbolt/tb.c
> > +++ b/drivers/thunderbolt/tb.c
> > @@ -89,6 +89,7 @@ static void tb_dp_resource_unavailable(struct tb *tb, struct tb_port *port,
> >   				       const char *reason);
> >   static void tb_queue_dp_bandwidth_request(struct tb *tb, u64 route, u8 port,
> >   					  int retry, unsigned long delay);
> > +static void tb_dp_tunnel_active(struct tb_tunnel *tunnel, void *data);
> If possible move the whole function here instead of forward declaration.

It calls a bunch of helpers that are only defined further down and I'd 
have to move all of them as well (or forward declare them which defeats 
the purpose of doing that)


Sven