Re: [Libusb-devel] usb_release_interface() + usb_close() -> broke communication

[Johannes E. <joh...@er...>]

On Mon, Nov 08, 2004, Martin Vaillancourt <mva...@me...> wrote:
> I'm using the LibUsb0.1.8 since many months to test USB Mass Storage
> Device. It works fine on our ClipDrive and ClipDrive Bio products. (For
> Ref Only. http://www.memoryexpertsinc.com/en/clipdrive.php);
>  
> Today, I try another Mass Storage Device. This one has a Texa Instrument
> controller and a HDD of 40GB.
>  
> The problem is this one:
>  
> -I do this:
> *	usb_open(dev) + usb_claim_interface(). 
> *	Send CBW Commands (Ex. Test Unit Ready (00h), Write (2Ah), Read
> (28h), Read Capacity (25h), etc)
> *	This works fine, until that I release the interface and close
> the handle?
> Now, even if re-open and re-claim the interface return me successful
> message, I cannot send CBW commands anymore?
>  
> Does anyone has seen /solved this problem. I think that a usb_reset()
> could be a "patch", but I will prefer to fix the real problem.

What platform and kernel version are you using?

Atleast under Linux, I don't think that usb_release_interface() and
usb_close() will send any data to the device or reset any internal
state.

It would be interesting if you could release the interface and then
reclaim it without closing the device to see if the failure still
exists. That would allow us to determine if it's the release or the
close that is causing the problem.

JE