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

[Mika Westerberg <mika.westerberg@linux.intel.com>]

On Mon, Aug 24, 2026 at 04:13:44PM +0200, Sven Peter wrote:
> 
> 
> 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@vger.kernel.org
> > > Signed-off-by: Sven Peter <sven@kernel.org>
> > > ---
> > >   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)

Okay then this is fine.