[pyusb-users] Access Denied Error on Windows 7

[Richard Bryan]

Hi Wander,

I ran with PYUSB_DEBUG=debug and encountered the error. The log text when
the error occurred is here:

http://pastebin.com/kmqSrek9

Its the pyusb debug log intermingled with my program's logging information
as well. The first "Access Denied" error occurs at line 1527. There are
also a bunch '[Errno 10060] Operation timed out' errors that occur leading
up to the access denied error. Just looking at the pyusb log messages
around the time the errors are reported by my program, I didn't see
anything that looked relevant...

Richard


Date: Thu, 13 Nov 2014 09:54:31 -0200
From: Wander Lairson Costa <***@gmail.com>
Subject: Re: [pyusb-users] Access Denied Error on Windows 7
To: pyusb-users <pyusb-***@lists.sourceforge.net>
Message-ID:
<CAFsSK4ZsCYbR8eQETrDrcU0QU+f_
05bKShpWgQdE6SA5K=***@mail.gmail.com>
Content-Type: text/plain; charset=UTF-8

I'm frequently running into an "Access Denied (insufficient permissions)"
errors on Windows 7 (with libusb1 backend) during long-running usb

sessions

with a device. When this happens, I call reset() and dispose_resources()

on

the usb handle and then attempt to reenumerate it using usb.core.find(),

but

the Access Denied error keeps occurring until I unplug and replug the
device. Restarting the program alone doesnt fix it.

iirc, libusb reset operation is problematic under Windows, so better
to avoid it.

I have a multithreaded program, but interaction with pyusb is only ever

done

in the same, single thread.

This should not cause problems...

Anyone have any ideas what's going on? Or is this something I should ask
the libusb list about?

Could you please run you program with the environment variable
PYUSB_DEBUG=debug defined and report the logs?

Richard

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Best Regards,
Wander Lairson Costa

[Xiaofan Chen]

Post by Richard Bryan
Hi Wander,
I ran with PYUSB_DEBUG=debug and encountered the error. The log text when
http://pastebin.com/kmqSrek9
Its the pyusb debug log intermingled with my program's logging information
as well. The first "Access Denied" error occurs at line 1527. There are
also a bunch '[Errno 10060] Operation timed out' errors that occur leading
up to the access denied error. Just looking at the pyusb log messages
around the time the errors are reported by my program, I didn't see anything
that looked relevant...

You should probably ask in the libusb mailing list. Right now I can not
access your pastebin message but sometimes it is caused by the
device problem (device hangs and lost on the USB bus).

Please also make sure you are using libusb-1.0.19 which is the
latest release version.