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

[Greg KH <gregkh@linuxfoundation.org>]

On Tue, Jun 11, 2024 at 08:23:11PM +0300, Dmitry Smirnov wrote:
> 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");

ftrace is your friend, there is no need for debug lines like this
anymore.

> +
> +	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");

Same here, not needed.

thanks,

greg k-h