RE: [EXT] Re: [PATCH] usb: typec: tcpm: fix create duplicate source/sink-capabilities file

[Xu Yang <xu.yang_2@nxp.com>]

Hi,

> -----Original Message-----
> From: Xu Yang
> Sent: Friday, December 16, 2022 2:41 PM
> To: Guenter Roeck <linux@roeck-us.net>; heikki.krogerus@linux.intel.com
> Cc: gregkh@linuxfoundation.org; linux-usb@vger.kernel.org; dl-linux-imx <linux-imx@nxp.com>; Jun Li <jun.li@nxp.com>
> Subject: RE: [EXT] Re: [PATCH] usb: typec: tcpm: fix create duplicate source/sink-capabilities file
> 
> Hi Guenter,
> 
> > -----Original Message-----
> > From: Guenter Roeck <groeck7@gmail.com> On Behalf Of Guenter Roeck
> > Sent: Friday, December 16, 2022 1:13 PM
> > To: Xu Yang <xu.yang_2@nxp.com>; heikki.krogerus@linux.intel.com
> > Cc: gregkh@linuxfoundation.org; linux-usb@vger.kernel.org; dl-linux-imx <linux-imx@nxp.com>; Jun Li <jun.li@nxp.com>
> > Subject: [EXT] Re: [PATCH] usb: typec: tcpm: fix create duplicate source/sink-capabilities file
> >
> > Caution: EXT Email
> >
> > On 12/15/22 19:31, Xu Yang wrote:
> > > After soft reset has completed, an Explicit Contract negotiation occurs.
> > > The sink device will receive source capabilitys again. This will cause
> > > a duplicate source-capabilities file be created.
> > >
> > > And the kernel will dump:
> > > sysfs: cannot create duplicate filename '/devices/virtual/usb_power_delivery/pd1/source-capabilities'
> > >
> > > This will unregister existing capabilities before register new one.
> > >
> > > Fixes: 8203d26905ee ("usb: typec: tcpm: Register USB Power Delivery Capabilities")
> > > cc: <stable@vger.kernel.org>
> > > Signed-off-by: Xu Yang <xu.yang_2@nxp.com>
> > > ---
> > >   drivers/usb/typec/tcpm/tcpm.c | 6 ++++++
> > >   1 file changed, 6 insertions(+)
> > >
> > > diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> > > index 904c7b4ce2f0..02d8a704db95 100644
> > > --- a/drivers/usb/typec/tcpm/tcpm.c
> > > +++ b/drivers/usb/typec/tcpm/tcpm.c
> > > @@ -2371,6 +2371,9 @@ static int tcpm_register_source_caps(struct tcpm_port *port)
> > >       if (IS_ERR(port->partner_pd))
> > >               return PTR_ERR(port->partner_pd);
> > >
> > > +     /* remove existing capabilities since got new one */
> > > +     usb_power_delivery_unregister_capabilities(port->partner_source_caps);
> > > +
> > >       memcpy(caps.pdo, port->source_caps, sizeof(u32) * port->nr_source_caps);
> > >       caps.role = TYPEC_SOURCE;
> > >
> > > @@ -2394,6 +2397,9 @@ static int tcpm_register_sink_caps(struct tcpm_port *port)
> > >       if (IS_ERR(port->partner_pd))
> > >               return PTR_ERR(port->partner_pd);
> > >
> > > +     /* remove existing capabilities since got new one */
> > > +     usb_power_delivery_unregister_capabilities(port->partner_sink_caps);
> > > +
> > >       memcpy(caps.pdo, port->sink_caps, sizeof(u32) * port->nr_sink_caps);
> > >       caps.role = TYPEC_SINK;
> > >
> >
> > Shouldn't usb_power_delivery_unregister_capabilities() be called from
> > the SOFT_RESET state handler ?
> 
> Although this issue is triggered by soft reset event, there is also
> other possibilities which may produce this behavior. Such as received
> 2rd source capability or use Get_Source_Cap message. It's a dynamic
> process even after source/sink is ready. So I think it's better to handle
> it in tcpm_register_source/sink_caps(). Not sure if this is reasonable.
> 
> Thanks,
> Xu Yang

Do you have any other comments or suggestions with this patch?

Thanks,
Xu Yang

> 
> >
> > Guenter