Re: [libusb] Timeouts then Access Denied Errors on Win 7

[Tim R. <ti...@pr...>]

Richard Bryan wrote:
> I have a program that uses pyusb with libusb-1.0.19-rc2 and the
> libusbk 3.0.7 driver on windows 7 64-bit (32-bit python program
> though).  I've been encountering issues during long running sessions
> of bulk transfers between a usb device.  I initially get a series of
> timeouts during transfers, and then "Access Denied (insufficient
> permissions)" errors.  The access denied errors occur indefinitely
> once they start. 

The logs are fairly confusing to me.  There are many, many calls to
libusb_init and libusb_exit.  Is that in your code, or is that part of
pyusb?

>From what I see, you do a read of 64 bytes at line 433, and you must
have specified a 16ms timeout.  That timer expires on line 438 and gets
returned to you on 449.  You then submit another read of 64 bytes on
line 451, apparently with a 0ms timeout.  So why does the error message
on line 469 say the timeout was in an attempt to write?  I don't see the
first write until line 473.

It looks like you're opening three different devices.  Is that true? 
Are you sure it's going to respond in 16ms?

-- 
Tim Roberts, ti...@pr...
Providenza & Boekelheide, Inc.