Revert "USB: serial: make bulk_out_size a lower limit"

This reverts commit 5083fd7bdfe6760577235a724cf6dccae13652c2.

A bulk-out size smaller than the end-point size is indeed valid. The
offending commit broke the usb-debug driver for EHCI debug devices,
which use 8-byte buffers.

Fixes: 5083fd7bdfe6 ("USB: serial: make bulk_out_size a lower limit")
Reported-by: "Li, Elvin" <elvin.li@intel.com>
Cc: stable <stable@vger.kernel.org>	# v3.15
Signed-off-by: Johan Hovold <johan@kernel.org>

1 files changed, 3 insertions, 2 deletions

diff --git a/drivers/usb/serial/usb-serial.c b/drivers/usb/serial/usb-serial.c
index 475723c006f9..19842370a07f 100644
--- a/drivers/usb/serial/usb-serial.c
+++ b/drivers/usb/serial/usb-serial.c
@@ -940,8 +940,9 @@ static int usb_serial_probe(struct usb_interface *interface,
                 port = serial->port[i];
                 if (kfifo_alloc(&port->write_fifo, PAGE_SIZE, GFP_KERNEL))
                         goto probe_error;
-                buffer_size = max_t(int, serial->type->bulk_out_size,
-                                                usb_endpoint_maxp(endpoint));
+                buffer_size = serial->type->bulk_out_size;
+                if (!buffer_size)
+                        buffer_size = usb_endpoint_maxp(endpoint);
                 port->bulk_out_size = buffer_size;
                 port->bulk_out_endpointAddress = endpoint->bEndpointAddress;