OPENCORES.ORG

Hello Everybody,

Monisha,
Can you send some CATC captures ?

pratap

On 8/9/05, Monisha Barooah <monisha.b@s...> wrote:
> Hello Everybody,
>    I had some issues in the enumeration sequence in our EHCI driver and so
> thought of putting forth a query in this mailing list.
>  
>    We are writting a customized EHCI driver and not using any of the
> components of the windows USB stack(class drivers, USBD and HC driver). A
> standalone EHCI-HC driver in the windows kernel we are developing to which
> requests are provided through an application.
>  
>    We are facing issues here with the enumeration sequence to be done for
> the split transactions. 
>  
>    Can anyone help us in providing pointers as to what is the sequence to be
> followed for the enumeration sequence involving a FS device connected to a
> HS hub? We have currently not yet implemented the Periodic Transfers...so is
> there any way to perform the hub configuration without using the interrupt
> endpoint corresponding to the hub device as mentioned in the specs? 
>  
>    We are trying to do the enumeration/configuration with our implementation
> of the asynchronous schedule alone and able to figure out onto which port of
> the hub, the FS device is connected to. 
>  
>    After performing the normal sequence of enumeration with the hub(HS
> device), we get the number of ports in the hub from the Hub Descriptor and
> use that value to power up all the hub ports. After that, we issue the
> ClearFeature request with C_PORT_CONNECTION feature and an issue of
> GetPortStatus after this allows us to know the port to which the device is
> connected. 
>  
>   After this we try to repeat the enumeration sequence for the FS device
> through the corresponding hub port.
>  
>   We issue the GetDevice Descriptor, Port Reset, Set Address, GetDevice
> Descriptor, Get configuration descriptor, Set configuration requests in a
> sequence for the FS enumeration and have provided the required delays of 2ms
> after the Set Address request.
>  
>   Note that we are providing in with all the delays required for the device
> attachments, delays before issuing a port reset etc. as mentioned in the USB
> specs.
>  
>   But we are still not able to consistently complete the split enumeration
> process through the hub with this approach. This process works sometimes but
> sometimes it results in a STALL of the endpoint and does not get through.
> Sometimes some extra packets IN/OUT packets are observed in between the
> enumeration sequqnce leading to a STALL.
>  
>   We have now provided a ClearFeature request for clearing ENDPOINT Halt so
> as to carry out the sequence till completion but still facing issues.
>  
>   Can anyone let know if there is some serious problem with this approach?
> Is it that the behavior of the system will never be stable if we adopt this
> strategy for enumeration without using the interrupt endpoint of the hub? Do
> we need to incorporate functionalities of the hub driver in our HC driver
> code for this? Note that we cannot use the hub driver currently existing
> with the windows as the three USB layers in the windows stack are bundled
> together and we are bypassing the stack.
>  
>   Thanking you in advance for the help.
>  
> With Regards,
> Monisha.
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> _______________________________________________
> http://www.opencores.org/mailman/listinfo/usb
> 
> 

-- 
**********************************************
Pratap Narayan Singh
STMicroelectronics
Plot No 2&3
Noida
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