Re: [pyusb-users] "large" writes fail?

[Jeffrey N. <jsn...@su...>]

Hi Karl,

Is it possible you're exceeding the default timeout for write() with 
your large data set? I just checked pyusb's source, and it looks like if 
you don't pass a timeout it uses 1000. That would explain why you're 
sending some data, but not all of it.

Try changing self.ep_out.write(data) to self.ep_out.write(data, 
timeout=0) or self.ep_out.write(data, timeout=10000) and see if that helps.

Best Regards,
Jeff

Jeffrey Nichols
Suprock Technologies, LLC
Phone: (603) 479-3408
Fax: (888) 629-4158
www.suprocktech.com

On 8/29/2015 10:17 PM, Karl Palsson wrote:
> -----BEGIN PGP SIGNED MESSAGE-----
> Hash: SHA1
>
> It's quite possible I'm doing something wrong in my device firmware, but
> I'm not sure how my device side can care, so...
>
> My device firmware is meant to be compatible with the linux gadget zero
> source/sink function, so I should be able to write as much as I like to
> it.  And, mostly, this seems to be true.  I can write 64, 640, 1000,
> 5000, bigger and bigger, but around 400k, it starts to fail the
> assertions.  The exact number of bytes written out is not consistent
> every time, but is around 450000.    What causes this, and is it
> something I'm doing?
>
>      def test_write_perf2(self):
>          ts = datetime.datetime.now()
>          txc = 0
>          data = [x & 0xff for x in range(500 * 1024)]
>          w = self.ep_out.write(data)
>          self.assertEqual(w, len(data), "Should have written all bytes plz")
>          txc += w
>          te = datetime.datetime.now() - ts
>          print("wrote %s bytes in %s for %s kps" % (txc, te, self.tput(txc, te)))
>
>
> Failure
> Traceback (most recent call last):
>    File "/home/karlp/src/libopencm3-examples/tests/gadget-zero/test_gadget0.py", line 172, in test_write_perf2
>      self.assertEqual(w, len(data), "Should have written all bytes plz")
> AssertionError: 455680 != 512000 : Should have written all bytes plz
>
> Failure
> Traceback (most recent call last):
>    File "/home/karlp/src/libopencm3-examples/tests/gadget-zero/test_gadget0.py", line 172, in test_write_perf2
>      self.assertEqual(w, len(data), "Should have written all bytes plz")
> AssertionError: 456896 != 512000 : Should have written all bytes plz
>
>
> Cheers,
> Karl P
>
> - -- 
> Sent using Mailpile, Free Software from www.mailpile.is
>
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