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From: Icenowy Zheng <icenowy@aosc.io>
To: Guenter Roeck <linux@roeck-us.net>,
	Heikki Krogerus <heikki.krogerus@linux.intel.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc: linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
	Icenowy Zheng <icenowy@aosc.io>
Subject: [PATCH] usb: typec: tcpm: always rediscover when swapping DR
Date: Fri, 13 Aug 2021 12:31:31 +0800	[thread overview]
Message-ID: <20210813043131.833006-1-icenowy@aosc.io> (raw)

Currently, TCPM code omits discover when swapping to gadget, and assume
that no altmodes are available when swapping from gadget. However, we do
send discover when we get attached as gadget -- this leads to modes to be
discovered twice when attached as gadget and then swap to host.

Always re-send discover when swapping DR, regardless of what change is
being made; and because of this, the assumption that no altmodes are
registered with gadget role is broken, and altmodes de-registeration is
always needed now.

Signed-off-by: Icenowy Zheng <icenowy@aosc.io>
---
 drivers/usb/typec/tcpm/tcpm.c | 9 ++++-----
 1 file changed, 4 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index b9bb63d749ec..ab6d0d51ee1c 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -4495,15 +4495,14 @@ static void run_state_machine(struct tcpm_port *port)
 		tcpm_set_state(port, ready_state(port), 0);
 		break;
 	case DR_SWAP_CHANGE_DR:
-		if (port->data_role == TYPEC_HOST) {
-			tcpm_unregister_altmodes(port);
+		tcpm_unregister_altmodes(port);
+		if (port->data_role == TYPEC_HOST)
 			tcpm_set_roles(port, true, port->pwr_role,
 				       TYPEC_DEVICE);
-		} else {
+		else
 			tcpm_set_roles(port, true, port->pwr_role,
 				       TYPEC_HOST);
-			port->send_discover = true;
-		}
+		port->send_discover = true;
 		tcpm_ams_finish(port);
 		tcpm_set_state(port, ready_state(port), 0);
 		break;
-- 
2.30.2

             reply	other threads:[~2021-08-13  4:32 UTC|newest]

Thread overview: 16+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2021-08-13  4:31 Icenowy Zheng [this message]
2021-08-17  9:36 ` Heikki Krogerus
2021-08-17  9:41   ` Icenowy Zheng
2021-08-17 11:00     ` Heikki Krogerus
2021-08-18 13:56       ` Greg Kroah-Hartman
2021-08-18 14:02         ` Icenowy Zheng
2021-08-18 14:40           ` Greg Kroah-Hartman
2021-08-18 16:13             ` Kyle Tso
2021-08-18 16:17               ` Icenowy Zheng
2021-08-18 16:24               ` Icenowy Zheng
2021-08-17 15:13   ` Guenter Roeck
2021-08-18  8:02     ` Kyle Tso
2021-08-18  8:16       ` Kyle Tso
2021-08-18  9:20       ` Icenowy Zheng
2021-08-18  9:27       ` Icenowy Zheng
2021-08-18 10:47         ` Kyle Tso

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