[v1] usb: typec: tcpm: advance vdm_discovery_state on Discover Identity Not_Supported

[PATCH] usb: typec: tcpm: advance vdm_discovery_state on Discover Identity Not_Supported

Posted by Xu Yang 1 week, 4 days ago

From: Xu Yang <xu.yang_2@nxp.com>

Commit fa4d0a7cd036 ("usb: typec: tcpm: fix Discover Identity retry loop
on Control Message reject") advances vdm_discovery_state to
VDM_DISCOVERY_COMPLETE when a CMDT_RSP_NAK is received, but it does not
advance the state when a non-modal port returns PD_CTRL_NOT_SUPP.

This can re-arm another vdm_discovery_work if the port is going to
respond with PD_CTRL_NOT_SUPP to the partner.

  tcpm_pd_handle_msg(port, PD_MSG_CTRL_NOT_SUPP, NONE_AMS);
    tcpm_queue_message();
      mod_tcpm_delayed_work();
        tcpm_state_machine_work()
          tcpm_send_queued_message()  -> send PD_MSG_CTRL_NOT_SUPP
          run_state_machine()
            case SRC_READY:
            case SNK_READY:
              mod_vdm_discovery_delayed_work(port, 0);

If both the port and its partner do not support modal operation, they
will send DISCOVER_IDENTITY to each other infinitely.

Advance vdm_discovery_state to VDM_DISCOVERY_COMPLETE in this path as
well, mirroring the existing handling for the SVDM CMDT_RSP_NAK case.

Fixes: fa4d0a7cd036 ("usb: typec: tcpm: fix Discover Identity retry loop on Control Message reject")
Signed-off-by: Xu Yang <xu.yang_2@nxp.com>
---
 drivers/usb/typec/tcpm/tcpm.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index 2d6b14aa2085..cc9ea5d5e78a 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -3891,6 +3891,9 @@ static void tcpm_pd_ctrl_request(struct tcpm_port *port,
 		case SRC_READY:
 		case SNK_READY:
 			if (port->vdm_state > VDM_STATE_READY) {
+				if (port->ams == DISCOVER_IDENTITY)
+					tcpm_update_vdm_discovery_state(port,
+									VDM_DISCOVERY_COMPLETE);
 				port->vdm_state = VDM_STATE_DONE;
 				if (tcpm_vdm_ams(port))
 					tcpm_ams_finish(port);
-- 
2.34.1

Re: [PATCH] usb: typec: tcpm: advance vdm_discovery_state on Discover Identity Not_Supported

Posted by Heikki Krogerus 1 week ago

On Mon, Sep 14, 2026 at 05:38:28PM +0800, Xu Yang wrote:
> From: Xu Yang <xu.yang_2@nxp.com>
> 
> Commit fa4d0a7cd036 ("usb: typec: tcpm: fix Discover Identity retry loop
> on Control Message reject") advances vdm_discovery_state to
> VDM_DISCOVERY_COMPLETE when a CMDT_RSP_NAK is received, but it does not
> advance the state when a non-modal port returns PD_CTRL_NOT_SUPP.
> 
> This can re-arm another vdm_discovery_work if the port is going to
> respond with PD_CTRL_NOT_SUPP to the partner.
> 
>   tcpm_pd_handle_msg(port, PD_MSG_CTRL_NOT_SUPP, NONE_AMS);
>     tcpm_queue_message();
>       mod_tcpm_delayed_work();
>         tcpm_state_machine_work()
>           tcpm_send_queued_message()  -> send PD_MSG_CTRL_NOT_SUPP
>           run_state_machine()
>             case SRC_READY:
>             case SNK_READY:
>               mod_vdm_discovery_delayed_work(port, 0);
> 
> If both the port and its partner do not support modal operation, they
> will send DISCOVER_IDENTITY to each other infinitely.
> 
> Advance vdm_discovery_state to VDM_DISCOVERY_COMPLETE in this path as
> well, mirroring the existing handling for the SVDM CMDT_RSP_NAK case.
> 
> Fixes: fa4d0a7cd036 ("usb: typec: tcpm: fix Discover Identity retry loop on Control Message reject")

I can't find that commit from anywhere?

Thanks,

> Signed-off-by: Xu Yang <xu.yang_2@nxp.com>
> ---
>  drivers/usb/typec/tcpm/tcpm.c | 3 +++
>  1 file changed, 3 insertions(+)
> 
> diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
> index 2d6b14aa2085..cc9ea5d5e78a 100644
> --- a/drivers/usb/typec/tcpm/tcpm.c
> +++ b/drivers/usb/typec/tcpm/tcpm.c
> @@ -3891,6 +3891,9 @@ static void tcpm_pd_ctrl_request(struct tcpm_port *port,
>  		case SRC_READY:
>  		case SNK_READY:
>  			if (port->vdm_state > VDM_STATE_READY) {
> +				if (port->ams == DISCOVER_IDENTITY)
> +					tcpm_update_vdm_discovery_state(port,
> +									VDM_DISCOVERY_COMPLETE);
>  				port->vdm_state = VDM_STATE_DONE;
>  				if (tcpm_vdm_ams(port))
>  					tcpm_ams_finish(port);
> -- 
> 2.34.1

-- 
heikki

Re: [PATCH] usb: typec: tcpm: advance vdm_discovery_state on Discover Identity Not_Supported

Posted by Xu Yang 4 days, 7 hours ago

Hi Heikki,

On Fri, Sep 18, 2026 at 09:53:17AM +0200, Heikki Krogerus wrote:
> On Mon, Sep 14, 2026 at 05:38:28PM +0800, Xu Yang wrote:
> > From: Xu Yang <xu.yang_2@nxp.com>
> > 
> > Commit fa4d0a7cd036 ("usb: typec: tcpm: fix Discover Identity retry loop
> > on Control Message reject") advances vdm_discovery_state to
> > VDM_DISCOVERY_COMPLETE when a CMDT_RSP_NAK is received, but it does not
> > advance the state when a non-modal port returns PD_CTRL_NOT_SUPP.
> > 
> > This can re-arm another vdm_discovery_work if the port is going to
> > respond with PD_CTRL_NOT_SUPP to the partner.
> > 
> >   tcpm_pd_handle_msg(port, PD_MSG_CTRL_NOT_SUPP, NONE_AMS);
> >     tcpm_queue_message();
> >       mod_tcpm_delayed_work();
> >         tcpm_state_machine_work()
> >           tcpm_send_queued_message()  -> send PD_MSG_CTRL_NOT_SUPP
> >           run_state_machine()
> >             case SRC_READY:
> >             case SNK_READY:
> >               mod_vdm_discovery_delayed_work(port, 0);
> > 
> > If both the port and its partner do not support modal operation, they
> > will send DISCOVER_IDENTITY to each other infinitely.
> > 
> > Advance vdm_discovery_state to VDM_DISCOVERY_COMPLETE in this path as
> > well, mirroring the existing handling for the SVDM CMDT_RSP_NAK case.
> > 
> > Fixes: fa4d0a7cd036 ("usb: typec: tcpm: fix Discover Identity retry loop on Control Message reject")
> 
> I can't find that commit from anywhere?

It's a mistake, and I sent v2 to correct it:
https://lore.kernel.org/linux-usb/20260916043957.3362995-1-xu.yang_2@oss.nxp.com/

Thanks,
Xu Yang