When a driver doesn't know how much data a device is going to send, the buffer size should be at least as big as the endpoint's maxpacket value. The serial drivers don't follow this rule; many of them request only 256-byte bulk-in buffers. As a result, they suffer overflow errors if a high-speed device wants to send a lot of data, because high-speed bulk endpoints are required to have a maxpacket size of 512. This patch (as1450) fixes the problem by using the driver's bulk_in_size value as a minimum, always allocating buffers no smaller than the endpoint's maxpacket size. Signed-off-by: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx> Tested-by: Flynn Marquardt <flynn@xxxxxxxxxx> CC: <stable@xxxxxxxxxx> --- drivers/usb/serial/usb-serial.c | 5 ++--- include/linux/usb/serial.h | 3 ++- 2 files changed, 4 insertions(+), 4 deletions(-) Index: usb-2.6/include/linux/usb/serial.h =================================================================== --- usb-2.6.orig/include/linux/usb/serial.h +++ usb-2.6/include/linux/usb/serial.h @@ -191,7 +191,8 @@ static inline void usb_set_serial_data(s * @id_table: pointer to a list of usb_device_id structures that define all * of the devices this structure can support. * @num_ports: the number of different ports this device will have. - * @bulk_in_size: bytes to allocate for bulk-in buffer (0 = end-point size) + * @bulk_in_size: minimum number of bytes to allocate for bulk-in buffer + * (0 = end-point size) * @bulk_out_size: bytes to allocate for bulk-out buffer (0 = end-point size) * @calc_num_ports: pointer to a function to determine how many ports this * device has dynamically. It will be called after the probe() Index: usb-2.6/drivers/usb/serial/usb-serial.c =================================================================== --- usb-2.6.orig/drivers/usb/serial/usb-serial.c +++ usb-2.6/drivers/usb/serial/usb-serial.c @@ -911,9 +911,8 @@ int usb_serial_probe(struct usb_interfac dev_err(&interface->dev, "No free urbs available\n"); goto probe_error; } - buffer_size = serial->type->bulk_in_size; - if (!buffer_size) - buffer_size = le16_to_cpu(endpoint->wMaxPacketSize); + buffer_size = max_t(int, serial->type->bulk_in_size, + le16_to_cpu(endpoint->wMaxPacketSize)); port->bulk_in_size = buffer_size; port->bulk_in_endpointAddress = endpoint->bEndpointAddress; port->bulk_in_buffer = kmalloc(buffer_size, GFP_KERNEL); -- To unsubscribe from this list: send the line "unsubscribe linux-usb" in the body of a message to majordomo@xxxxxxxxxxxxxxx More majordomo info at http://vger.kernel.org/majordomo-info.html
