Re: [PATCH 02/17] Input: serio - attach manual drivers through the driver core

[Dmitry Torokhov]

On Thu, Nov 05, 2026 at 09:19:40PM +0200, Leon Romanovsky wrote:
> On Thu, Nov 05, 2026 at 09:05:29AM -0800, Dmitry Torokhov wrote:
> > On Thu, Nov 05, 2026 at 01:42:15PM +0200, Leon Romanovsky wrote:
> > > From: Leon Romanovsky <leonro@xxxxxxxxxx>
> > > 
> > > Manual serio binding connects a driver before driver core can admit the
> > > device. A rejected binding therefore arrives after functional setup.
> > > 
> > > Keep the port ID check and use device_driver_attach() for the existing bus
> > > probe path. Driver core then serializes admission and handles probe failure
> > > before publishing the binding.
> > > 
> > > Signed-off-by: Leon Romanovsky <leonro@xxxxxxxxxx>
> > > ---
> > >  drivers/input/serio/serio.c | 24 +++---------------------
> > >  1 file changed, 3 insertions(+), 21 deletions(-)
> > > 
> > > diff --git a/drivers/input/serio/serio.c b/drivers/input/serio/serio.c
> > > index 54dd26249b027..604440244c1ca 100644
> > > --- a/drivers/input/serio/serio.c
> > > +++ b/drivers/input/serio/serio.c
> > > @@ -81,28 +81,10 @@ static int serio_match_port(const struct serio_device_id *ids, struct serio *ser
> > >  
> > >  static int serio_bind_driver(struct serio *serio, struct serio_driver *drv)
> > >  {
> > > -	int error;
> > > -
> > > -	if (serio_match_port(drv->id_table, serio)) {
> > > -
> > > -		serio->dev.driver = &drv->driver;
> > > -		if (serio_connect_driver(serio, drv)) {
> > > -			serio->dev.driver = NULL;
> > > -			return -ENODEV;
> > > -		}
> > > +	if (!serio_match_port(drv->id_table, serio))
> > > +		return 0;
> > >  
> > > -		error = device_bind_driver(&serio->dev);
> > > -		if (error) {
> > > -			dev_warn(&serio->dev,
> > > -				 "device_bind_driver() failed for %s (%s) and %s, error: %d\n",
> > > -				 serio->phys, serio->name,
> > > -				 drv->description, error);
> > > -			serio_disconnect_driver(serio);
> > > -			serio->dev.driver = NULL;
> > > -			return error;
> > > -		}
> > > -	}
> > > -	return 0;
> > > +	return device_driver_attach(&drv->driver, &serio->dev);
> > 
> > I am not sure how safe it is, serio (and gameport) have pretty elaborate
> > structure and locking rules because they can recurse into themselves (to
> > support case of Synaptics touch-pads with pass-through PS/2 ports).
> > 
> > But this call is for user-initiated probing anyways, I am not sure if it
> > even needs "trust" handling.
> 
> This patch does not change the locking; the lock was already held on paths such
> as the rescan path. This change makes that explicit.

Does this enforce synchronous probing?

Anyway, I would like to get rid of this special probing in serio core.
Given that the code path is only triggered by explicit user request I do
not believe we need to worry about supporting trust notion here, so
please drop it from the series.

Thanks.

-- 
Dmitry