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Date:   Thu, 16 Nov 2023 16:32:16 +0800
Mime-Version: 1.0
Message-ID: <20231116083221.1201892-1-guanyulin@google.com>
Subject: [PATCH] usb: typec: tcpm: skip checking port->send_discover in PD3.0
From:   Guan-Yu Lin <guanyulin@google.com>
To:     linux@roeck-us.net, heikki.krogerus@linux.intel.com,
        gregkh@linuxfoundation.org
Cc:     linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
        badhri@google.com, kyletso@google.com, albertccwang@google.com,
        Guan-Yu Lin <guanyulin@google.com>
Content-Type: text/plain; charset="UTF-8"
Precedence: bulk

The original Collison Avoidance mechanism, port->send_discover, avoids
the conflict when port partners start AMS almost the same time. However,
this mechanism is replaced by SINK_TX_OK and SINK_TX_NG. Skip the check
in PD3.0 to avoid the deadlock when source is requesting DR_SWAP where
sink is requesting DISCOVER_IDENTITY.

Signed-off-by: Guan-Yu Lin <guanyulin@google.com>
---
 drivers/usb/typec/tcpm/tcpm.c | 6 +++---
 1 file changed, 3 insertions(+), 3 deletions(-)

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index 058d5b853b57..ff3c171a3a75 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -2847,7 +2847,7 @@ static void tcpm_pd_ctrl_request(struct tcpm_port *port,
 					   PD_MSG_CTRL_NOT_SUPP,
 					   NONE_AMS);
 		} else {
-			if (port->send_discover) {
+			if (port->send_discover && port->negotiated_rev < PD_REV30) {
 				tcpm_queue_message(port, PD_MSG_CTRL_WAIT);
 				break;
 			}
@@ -2863,7 +2863,7 @@ static void tcpm_pd_ctrl_request(struct tcpm_port *port,
 					   PD_MSG_CTRL_NOT_SUPP,
 					   NONE_AMS);
 		} else {
-			if (port->send_discover) {
+			if (port->send_discover && port->negotiated_rev < PD_REV30) {
 				tcpm_queue_message(port, PD_MSG_CTRL_WAIT);
 				break;
 			}
@@ -2872,7 +2872,7 @@ static void tcpm_pd_ctrl_request(struct tcpm_port *port,
 		}
 		break;
 	case PD_CTRL_VCONN_SWAP:
-		if (port->send_discover) {
+		if (port->send_discover && port->negotiated_rev < PD_REV30) {
 			tcpm_queue_message(port, PD_MSG_CTRL_WAIT);
 			break;
 		}
-- 
2.43.0.rc0.421.g78406f8d94-goog