linux-kernel - [PATCH v2] usb: typec: tcpm: apply vbus before data bringup in tcpm_src

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Message-ID: <20250515014003.1681068-2-rdbabiera@google.com>
Date: Thu, 15 May 2025 01:40:02 +0000
From: RD Babiera <rdbabiera@...gle.com>
Cc: heikki.krogerus@...ux.intel.com, badhri@...gle.com, 
	gregkh@...uxfoundation.org, linux-usb@...r.kernel.org, 
	linux-kernel@...r.kernel.org, RD Babiera <rdbabiera@...gle.com>, stable@...r.kernel.org
Subject: [PATCH v2] usb: typec: tcpm: apply vbus before data bringup in tcpm_src_attach

This patch fixes Type-C compliance test TD 4.7.6 - Try.SNK DRP Connect
SNKAS.

tVbusON has a limit of 275ms when entering SRC_ATTACHED. Compliance
testers can interpret the TryWait.Src to Attached.Src transition after
Try.Snk as being in Attached.Src the entire time, so ~170ms is lost
to the debounce timer.

Setting the data role can be a costly operation in host mode, and when
completed after 100ms can cause Type-C compliance test check TD 4.7.5.V.4
to fail.

Turn VBUS on before tcpm_set_roles to meet timing requirement.

Fixes: f0690a25a140 ("staging: typec: USB Type-C Port Manager (tcpm)")
Cc: stable@...r.kernel.org
Signed-off-by: RD Babiera <rdbabiera@...gle.com>
Reviewed-by: Badhri Jagan Sridharan <badhri@...gle.com>
Reviewed-by: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
---
Changes since v1:
* Rebased on top of usb-linus for v6.15
---
 drivers/usb/typec/tcpm/tcpm.c | 32 ++++++++++++++++----------------
 1 file changed, 16 insertions(+), 16 deletions(-)

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index 8adf6f954633..05c62a1673af 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -4353,16 +4353,6 @@ static int tcpm_src_attach(struct tcpm_port *port)
 
 	tcpm_enable_auto_vbus_discharge(port, true);
 
-	ret = tcpm_set_roles(port, true, TYPEC_SOURCE, tcpm_data_role_for_source(port));
-	if (ret < 0)
-		return ret;
-
-	if (port->pd_supported) {
-		ret = port->tcpc->set_pd_rx(port->tcpc, true);
-		if (ret < 0)
-			goto out_disable_mux;
-	}
-
 	/*
 	 * USB Type-C specification, version 1.2,
 	 * chapter 4.5.2.2.8.1 (Attached.SRC Requirements)
@@ -4372,12 +4362,22 @@ static int tcpm_src_attach(struct tcpm_port *port)
 	    (polarity == TYPEC_POLARITY_CC2 && port->cc1 == TYPEC_CC_RA)) {
 		ret = tcpm_set_vconn(port, true);
 		if (ret < 0)
-			goto out_disable_pd;
+			return ret;
 	}
 
 	ret = tcpm_set_vbus(port, true);
 	if (ret < 0)
 		goto out_disable_vconn;
+	
+	ret = tcpm_set_roles(port, true, TYPEC_SOURCE, tcpm_data_role_for_source(port));
+	if (ret < 0)
+		goto out_disable_vbus;
+
+	if (port->pd_supported) {
+		ret = port->tcpc->set_pd_rx(port->tcpc, true);
+		if (ret < 0)
+			goto out_disable_mux;
+	}
 
 	port->pd_capable = false;
 
@@ -4389,14 +4389,14 @@ static int tcpm_src_attach(struct tcpm_port *port)
 
 	return 0;
 
-out_disable_vconn:
-	tcpm_set_vconn(port, false);
-out_disable_pd:
-	if (port->pd_supported)
-		port->tcpc->set_pd_rx(port->tcpc, false);
 out_disable_mux:
 	tcpm_mux_set(port, TYPEC_STATE_SAFE, USB_ROLE_NONE,
 		     TYPEC_ORIENTATION_NONE);
+out_disable_vbus:
+	tcpm_set_vbus(port, false);
+out_disable_vconn:
+	tcpm_set_vconn(port, false);
+
 	return ret;
 }
 

base-commit: 82f2b0b97b36ee3fcddf0f0780a9a0825d52fec3
-- 
2.49.0.1045.g170613ef41-goog