[pyusb-users] 回覆: help on win7: Entity not found

[CM-Wu B. - 吳. <be...@cm...>]

寄件者: Jonas Malaco via pyusb-users <pyu...@li...>
寄件日期: 2021年4月27日 下午 05:16
收件者: pyu...@li... <pyu...@li...>
副本: Jonas Malaco <jo...@pr...>
主旨: Re: [pyusb-users] help on win7: Entity not found

On Tue, Apr 27, 2021 at 08:18:09AM +0000, CM-Wu  Ben - 吳文鐘 wrote:
> Hi,
> I got a problem when dealing with control transfer on win7.
>
> After set backend(libusb1), find usb device, I can send standard/class USB request via dev.ctrl_transfer() successfully, but failed when sending vendor request.
>
> the reason is 'Entity not found'
> Is there any restrictions when sending vendor request?

Not generally, no.

But the OS driver may not support it (e.g. Windows Generic HID).

Try running with LIBUSB_DEBUG=4, that may give you some useful
information.
------------------

Thanks for your information.
I tried to run with LIBUSB_DEBUG=4, and found that it is windows HID driver that handle the request, which does not support it.

The device I'm testing is a composite device, which has audio interface within it.
Do windows audio driver support the handling of control transfer ?
If yes, is it possible to send control transfer via audio driver? how to do it using libusb backend?
Thanks



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