Not able to read USB speed and descriptor

Not able to read USB speed and descriptor

[Prabhu Chawandi]

Hi all,

   I ma not able to read the USB descriptor and speeed, while I can
read and write into the storage device..

What might be the reason for that ?

regards,
Prabhu

Re: Not able to read USB speed and descriptor

[Rajaram R]

On Tue, Jun 23, 2009 at 9:27 PM, Prabhu
Chawandi<prabhu.chavandi@gmail.com> wrote:
> Hi all,
>
>   I ma not able to read the USB descriptor and speeed, while I can
> read and write into the storage device..
>
> What might be the reason for that ?

Where is the code ?

>
> regards,
> Prabhu
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Re: Not able to read USB speed and descriptor

[Prabhu Chawandi]

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.


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


Any inputs ? ,,,,,

On Tue, Jun 23, 2009 at 6:57 PM, Prabhu
Chawandi<prabhu.chavandi@gmail.com> wrote:
> Hi all,
>
>   I ma not able to read the USB descriptor and speeed, while I can
> read and write into the storage device..
>
> What might be the reason for that ?
>
> regards,
> Prabhu
>

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