linux-kernel - [PATCH v2] usb: typec: tcpm: Fix altmode re-registration causes sysfs create fail

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Date:   Mon, 9 Jan 2023 09:34:52 +0800
From:   <cy_huang@...htek.com>
To:     <linux@...ck-us.net>, <heikki.krogerus@...ux.intel.com>,
        <matthias.bgg@...il.com>
CC:     <gregkh@...uxfoundation.org>, <gene_chen@...htek.com>,
        <linux-usb@...r.kernel.org>, <linux-kernel@...r.kernel.org>,
        <linux-arm-kernel@...ts.infradead.org>,
        <linux-mediatek@...ts.infradead.org>,
        ChiYuan Huang <cy_huang@...htek.com>, <stable@...r.kernel.org>
Subject: [PATCH v2] usb: typec: tcpm: Fix altmode re-registration causes sysfs create fail

From: ChiYuan Huang <cy_huang@...htek.com>

There's the altmode re-registeration issue after data role
swap (DR_SWAP).

Comparing to USBPD 2.0, in USBPD 3.0, it loose the limit that only DFP
can initiate the VDM command to get partner identity information.

For a USBPD 3.0 UFP device, it may already get the identity information
from its port partner before DR_SWAP. If DR_SWAP send or receive at the
mean time, 'send_discover' flag will be raised again. It causes discover
identify action restart while entering ready state. And after all
discover actions are done, the 'tcpm_register_altmodes' will be called.
If old altmode is not unregistered, this sysfs create fail can be found.

In 'DR_SWAP_CHANGE_DR' state case, only DFP will unregister altmodes.
For UFP, the original altmodes keep registered.

This patch fix the logic that after DR_SWAP, 'tcpm_unregister_altmodes'
must be called whatever the current data role is.

Reviewed-by: Macpaul Lin <macpaul.lin@...iatek.com>
Fixes: ae8a2ca8a221 ("usb: typec: Group all TCPCI/TCPM code together)
Reported-by: TommyYl Chen <tommyyl.chen@...iatek.com>
Cc: stable@...r.kernel.org
Signed-off-by: ChiYuan Huang <cy_huang@...htek.com>
---
Since v2:
1. Correct the mail sent from Richtek.
2. Add 'Reviewed-by' tag.

---
 drivers/usb/typec/tcpm/tcpm.c | 7 +++----
 1 file changed, 3 insertions(+), 4 deletions(-)

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index 904c7b4..59b366b 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -4594,14 +4594,13 @@ 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);
-               }
                tcpm_ams_finish(port);
                tcpm_set_state(port, ready_state(port), 0);
                break;
--
2.7.4

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