usb: serial: silence all non-critical read errors

If a USB serial device is unplugged while there is an active program
using the device it may spam the logs with -EPROTO (71) messages as it
attempts to retry.

Most serial usb drivers (metro-usb, pl2303, mos7840, ...) only output
these messages for debugging.  The generic driver treats these as
errors.

Change the default output for the generic serial driver from error to
debug to silence these non-critical errors.

Signed-off-by: Jeremiah Mahler <jmmahler@gmail.com>
Signed-off-by: Johan Hovold <johan@kernel.org>

diff --git a/drivers/usb/serial/generic.c b/drivers/usb/serial/generic.c
index 1bd1922..2d7207b 100644 (file)
--- a/drivers/usb/serial/generic.c
+++ b/drivers/usb/serial/generic.c
@@ -373,7 +373,7 @@ void usb_serial_generic_read_bulk_callback(struct urb *urb)
                                                        __func__, urb->status);
                return;
        default:
-               dev_err(&port->dev, "%s - nonzero urb status: %d\n",
+               dev_dbg(&port->dev, "%s - nonzero urb status: %d\n",
                                                        __func__, urb->status);
                goto resubmit;
        }