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

From: Xu Yang

Date: Mon Sep 14 2026 - 06:13:58 EST


From: Xu Yang <xu.yang_2@xxxxxxx>

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@xxxxxxx>
---
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