Re: [Libusb-win32-devel] Libusb-win32-devel Digest, Vol 13, Issue 22

[Dan E. <dan...@ne...>]

Krakora, Robert V wrote:
>
> Dan:
>
> Yes, I see your point.  There are a couple of other filter drivers
> installed on my Windows XP SP2 PC.  Could they possibly be causing
> problems for set_configuration()?  I was trying to call
> set_configuration() originally from my driver and it had no effect.  I
> saw that it was commented out in pnp.c, so I commented it back in,
> rebuilt the libusb0.sys driver, installed it, rebooted my PC and saw
> that none of my USB devices were working.  When I set
> "MaximumTransferSize" to 65535 in pnp.c and repeated these steps my USB
> devices again functioned after the reboot.  ???  I believe HDD's Device
> Monitoring Studio installed a filter driver.
>
Well it wouldn't be the first time that Microsoft documentation was a 
bit light on the truth! Your experience suggests that the maximum 
transfer size field is doing something (contrary to the MS online docs).

Slightly off topic, there's also a MS app note stating that for a USB 
mass storage device to have an executable autorun on it, then it must 
have the removable bit clear in the response to the SCSI INQUIRY 
command. Well I've been looking at a U3 flash stick here on the 
analyzer, and it has that bit set! It has 2 luns, the main one for 
writing to, and a subsidiary one which appears as a CDROM drive (it 
fills the first byte of the SCSI INQUIRY command with a 5), and off 
which loads some application software which runs automatically.

As for your set configuration problem, have you turned on debugging in 
the driver and seen why the set configuration failed? I've never used 
libusb in filter mode.

Dan.