linux-kernel - [PATCH] usb: typec: intel_pmc_mux: Avoid connect request on disconnect

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Date:   Wed,  8 Jul 2020 17:24:41 -0700
From:   Prashant Malani <pmalani@...omium.org>
To:     gregkh@...uxfoundation.org
Cc:     linux-kernel@...r.kernel.org,
        Prashant Malani <pmalani@...omium.org>,
        Benson Leung <bleung@...omium.org>,
        Heikki Krogerus <heikki.krogerus@...ux.intel.com>,
        Rajmohan Mani <rajmohan.mani@...el.com>,
        linux-usb@...r.kernel.org (open list:USB TYPEC INTEL PMC MUX DRIVER)
Subject: [PATCH] usb: typec: intel_pmc_mux: Avoid connect request on disconnect

When pmc_usb_mux_set() is invoked when a device is disconnected, a valid
scenario is for state->alt == NULL and state->mode == TYPEC_STATE_USB.

In such cases, if a pmc_usb_disconnect() has already been issued (from
either pmc_usb_set_orientation() when orientation ==
TYPEC_ORIENTATION_NONE, or pmc_usb_set_role() when role ==
USB_ROLE_NONE), a pmc_usb_connect() will be issued despite no peripheral
being present.

This confuses the PMC and leads to all subsequent PMC IPC requests
returning errors due to timeout.

To prevent this, return early if the port orientation or role is already
set to none.

Cc: Benson Leung <bleung@...omium.org>
Cc: Heikki Krogerus <heikki.krogerus@...ux.intel.com>
Cc: Rajmohan Mani <rajmohan.mani@...el.com>
Fixes: f3c1c41ebc67 ("usb: typec: intel_pmc_mux: Add support for USB4")
Signed-off-by: Prashant Malani <pmalani@...omium.org>
---
 drivers/usb/typec/mux/intel_pmc_mux.c | 3 +++
 1 file changed, 3 insertions(+)

diff --git a/drivers/usb/typec/mux/intel_pmc_mux.c b/drivers/usb/typec/mux/intel_pmc_mux.c
index 2aba07c7b221..e4021e13af40 100644
--- a/drivers/usb/typec/mux/intel_pmc_mux.c
+++ b/drivers/usb/typec/mux/intel_pmc_mux.c
@@ -310,6 +310,9 @@ pmc_usb_mux_set(struct typec_mux *mux, struct typec_mux_state *state)
 {
 	struct pmc_usb_port *port = typec_mux_get_drvdata(mux);
 
+	if (port->orientation == TYPEC_ORIENTATION_NONE || port->role == USB_ROLE_NONE)
+		return 0;
+
 	if (state->mode == TYPEC_STATE_SAFE)
 		return pmc_usb_mux_safe_state(port);
 	if (state->mode == TYPEC_STATE_USB)
-- 
2.27.0.383.g050319c2ae-goog