[PATCH V3] usb: mos7840: Fix hangup after suspend

Dmitry Smirnov
2024-06-11T17:32:44Z

This patch addresses a kernel hang issue with the mos7840 driver when
PC resuming from a suspend with a device connected to the serial port.

This patch introduces two new functions: mos7840_suspend() and mos7840_resume().

Tested with Delock 87414 USB 2.0 to 4x serial adapter.

Signed-off-by: Dmitry Smirnov <d.smirnov@inbox.lv>
---
V3: Addressed review comments from previous submits

drivers/usb/serial/mos7840.c | 51 ++++++++++++++++++++++++++++++++++++
1 file changed, 51 insertions(+)

diff --git a/drivers/usb/serial/mos7840.c b/drivers/usb/serial/mos7840.c
index 8b0308d84270..3e5f761f4925 100644
--- a/drivers/usb/serial/mos7840.c
+++ b/drivers/usb/serial/mos7840.c
@@ -1737,6 +1737,55 @@ static void mos7840_port_remove(struct usb_serial_port *port)
kfree(mos7840_port);
}

+static int mos7840_suspend(struct usb_serial *serial, pm_message_t message)
+{
+ struct moschip_port *mos7840_port;
+ struct usb_serial_port *port;
+ int i;
+
+ dev_dbg(&serial->interface->dev, "mos7840_suspend\n");
+
+ for (i = 0; i < serial->num_ports; ++i) {
+ port = serial->port[i];
+ if (!tty_port_initialized(&port->port))
+ continue;
+
+ mos7840_port = usb_get_serial_port_data(port);
+
+ usb_kill_urb(mos7840_port->read_urb);
+ mos7840_port->read_urb_busy = false;
+ }
+ return 0;
+}
+
+static int mos7840_resume(struct usb_serial *serial)
+{
+ struct moschip_port *mos7840_port;
+ struct usb_serial_port *port;
+ int res;
+ int i;
+
+ dev_dbg(&serial->interface->dev, "mos7840_resume\n");
+
+ for (i = 0; i < serial->num_ports; ++i) {
+ port = serial->port[i];
+ if (!tty_port_initialized(&port->port))
+ continue;
+
+ mos7840_port = usb_get_serial_port_data(port);
+
+ if (port->bulk_in_size) {
+ res = usb_submit_urb(mos7840_port->read_urb, GFP_NOIO);
+ if (res) {
+ usb_kill_urb(mos7840_port->read_urb);
+ mos7840_port->read_urb_busy = false;
+ }
+ }
+ }
+
+ return 0;
+}
+
static struct usb_serial_driver moschip7840_4port_device = {
.driver = {
.owner = THIS_MODULE,
@@ -1764,6 +1813,8 @@ static struct usb_serial_driver moschip7840_4port_device = {
.port_probe = mos7840_port_probe,
.port_remove = mos7840_port_remove,
.read_bulk_callback = mos7840_bulk_in_callback,
+ .suspend = mos7840_suspend,
+ .resume = mos7840_resume,
};

static struct usb_serial_driver * const serial_drivers[] = {

base-commit: c3f38fa61af77b49866b006939479069cd451173
--
2.45.1