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Date:   Mon, 13 Jul 2020 13:43:00 -0700
Message-Id: <20200713204300.345975-1-badhri@google.com>
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Subject: [PATCH] usb: typec: tcpm: Move to high priority workqueue for
 processing events
From:   Badhri Jagan Sridharan <badhri@google.com>
To:     Guenter Roeck <linux@roeck-us.net>,
        Heikki Krogerus <heikki.krogerus@linux.intel.com>,
        reg Kroah-Hartman <gregkh@linuxfoundation.org>
Cc:     linux-usb@vger.kernel.org, linux-kernel@vger.kernel.org,
        Badhri Jagan Sridharan <badhri@google.com>
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"tReceiverResponse 15 ms Section 6.6.2
The receiver of a Message requiring a response Shall respond
within tReceiverResponse in order to ensure that the
sender=E2=80=99s SenderResponseTimer does not expire."

When the cpu complex is busy running other lower priority
work items, TCPM's work queue sometimes does not get scheduled
on time to meet the above requirement from the spec.
Elevating the TCPM's work queue to higher priority allows
TCPM to meet tReceiverResponse in a busy system.

Signed-off-by: Badhri Jagan Sridharan <badhri@google.com>
---
 drivers/usb/typec/tcpm/tcpm.c | 2 +-
 1 file changed, 1 insertion(+), 1 deletion(-)

diff --git a/drivers/usb/typec/tcpm/tcpm.c b/drivers/usb/typec/tcpm/tcpm.c
index 82b19ebd7838e0..088b6f1fa1ff89 100644
--- a/drivers/usb/typec/tcpm/tcpm.c
+++ b/drivers/usb/typec/tcpm/tcpm.c
@@ -4747,7 +4747,7 @@ struct tcpm_port *tcpm_register_port(struct device *d=
ev, struct tcpc_dev *tcpc)
 	mutex_init(&port->lock);
 	mutex_init(&port->swap_lock);
=20
-	port->wq =3D create_singlethread_workqueue(dev_name(dev));
+	port->wq =3D alloc_ordered_workqueue("%s", WQ_HIGHPRI, dev_name(dev));
 	if (!port->wq)
 		return ERR_PTR(-ENOMEM);
 	INIT_DELAYED_WORK(&port->state_machine, tcpm_state_machine_work);
--=20
2.27.0.383.g050319c2ae-goog