2010/7/9 Xiaofan Chen <xiaof...@gmail.com>:
> On Sat, Jul 10, 2010 at 12:12 AM, Wander Lairson
> <wander.lair...@gmail.com> wrote:
>>> The problem was in a Copy&Paste error where i have defined the
>>> endpoint numbers as:
>>>
>>> TI_EP_BULK_UART1_OUT = 0x01
>>> TI_EP_BULK_UART1_OUT = 0x81
>>>
>>> And they should be:
>>>
>>> TI_EP_BULK_UART1_OUT = 0x01
>>> TI_EP_BULK_UART1_IN = 0x81
>>>
>>> and the tried to WRITE to an INPUT endpoint.
>>>
>>> Question: shouldnt this raise an exception on pyusb?
>>
>> Actually I dispatch the resquest to the underline library and trust on
>> it reporting this things.
>> But I can consider this kind of validation on PyUSB layer.
>>
>
> The only issue is with libusb-0.1 (now consider unsupported and
> won't fix by Daniel Drake) which masks the direction
> bit. libusb-win32 does not do that, libusb-1.0 does not do that.
>
> Reference:
> http://libusb.svn.sourceforge.net/viewvc/libusb/trunk/libusb/linux.c?revision=658&view=markup
>
> There are things like the following which Daniel Drake and many others
> consider bad thing to do.
I consider also, because it masks a misuse in the application layer.
But validating the
endpoint and returning an error might be a good ideia, like that:
int usb_interrupt_read(usb_dev_handle *dev, int ep, char *bytes, int size,
int timeout)
{
/* Ensure the endpoint address is correct */
if (ep & USB_ENDPOINT_IN) {
errno = EINVAL;
return -1;
}
Altough I prefer to trust on OS drivers doing this validation. If it
doesn't, it might have a good
reason to not do so.
>
> 310 int usb_interrupt_read(usb_dev_handle *dev, int ep, char *bytes, int
> size,
> 311 int timeout)
> 312 {
> 313 /* Ensure the endpoint address is correct */
> 314 ep |= USB_ENDPOINT_IN;
> 315 return usb_urb_transfer(dev, ep, USB_URB_TYPE_INTERRUPT, bytes, size,
> 316 timeout);
> 317 }
>
> 288 int usb_bulk_read(usb_dev_handle *dev, int ep, char *bytes, int size,
> 289 int timeout)
> 290 {
> 291 /* Ensure the endpoint address is correct */
> 292 ep |= USB_ENDPOINT_IN;
> 293 return usb_urb_transfer(dev, ep, USB_URB_TYPE_BULK, bytes, size,
> 294 timeout);
> 295 }
>
>
>
> --
> Xiaofan http://sourceforge.net/projects/libusb-win32/
>
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--
Best Regards,
Wander Lairson Costa
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