[PATCH] USB: debug port converter does not accept more than 8 byte packets

[Aleksey Gorelov]

Hi,

USB debug port only supports 8 byte rx/tx packets. Although spec implies that "if a packet larger than eight bytes is received from the remote computer, the device must break the larger packet into eight-byte packets before sending the data to the Debug Port", the real PLX NET20DC device does not handle it right - data is corrupted on debug port end if serial interface sends >8 byte urbs. Patch below fixes the issue by limiting tx urb to 8 byte.

Signed off by: Aleks Gorelov <***@yahoo.com>

--- a/drivers/usb/serial/usb_debug.c 2008-06-19 14:52:19.000000000 -0700
+++ b/drivers/usb/serial/usb_debug.c 2008-06-19 14:48:32.000000000 -0700
@@ -15,6 +15,8 @@
#include <linux/usb.h>
#include <linux/usb/serial.h>

+#define USB_DEBUG_MAX_PACKET_SIZE 8
+
static struct usb_device_id id_table [] = {
{ USB_DEVICE(0x0525, 0x127a) },
{ },
@@ -29,6 +31,12 @@
.no_dynamic_id = 1,
};

+int usb_debug_open (struct usb_serial_port *port, struct file *filp)
+{
+ port->bulk_out_size = USB_DEBUG_MAX_PACKET_SIZE;
+ return usb_serial_generic_open(port, filp);
+}
+
static struct usb_serial_driver debug_device = {
.driver = {
.owner = THIS_MODULE,
@@ -39,6 +47,7 @@
.num_bulk_in = NUM_DONT_CARE,
.num_bulk_out = NUM_DONT_CARE,
.num_ports = 1,
+ .open = usb_debug_open,
};

static int __init debug_init(void)