Re: Not able to read USB speed and descriptor

[Alan Stern]

On Wed, 24 Jun 2009, Prabhu Chawandi wrote:

> In the devio.c,
> 
>   I have added  a case to return the speed and other descriptors,
> 
> call :
>  ret = usb_control_msg(pRootHub, usb_sndctrlpipe(pRootHub, 0),
>                USB_REQ_CLEAR_FEATURE, USB_RT_PORT, USB_PORT_FEAT_POWER,
>                port_num + 1, NULL, 0, HZ);
> 
> The above call is returning err : -32 EPIPE.
> 
> The above call is working file for the rear port while the same is not
> working for the fromt port.

Is this question related to $SUBJECT?  I don't see any connection...

> Anythig am I missing ? I am testing it for mass stoage device...

In most host controllers for personal computers, the hardware does not
support turning off port power.

Alan Stern

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