Hi Simone,

On Tuesday 03 February 2009, Simone Freddio wrote:
> Hi Laurent,
>
>     here the results of my tests:
>
>     MaxPayloadTransferSize        Value Returned from device
> Result
>     0                                            128
>                               uvcvideo: USB isochronous frame lost (-71).
>     1                                            128
>                               uvcvideo: USB isochronous frame lost (-71).
>     42                                          128
>                               uvcvideo: USB isochronous frame lost (-71).
>     1024                                      1024
>                            works right with few USB iso frame lost
>     0xFFFF                                   3072
>                        no error but also no capture :-(
>
>     My conclusion is that MaxPayloadTransferSize, regardless of
> specification, is not readonly... seems to be that device round this
> value to the closest that is supported (see also my lsusb in file
> lsusb.txt).
>
>     I think that the right bandwidth allocation must be calculated in
> the driver and set up in the device (the same you have done for
> frameinterval value :-).

I'll see if I can compute an estimated maximum payload transfer size based on 
the information available to the driver, otherwise I will just just smaller 
allocations until one of them succeeds.

I should get a Vimicro camera soon that I will use to develop and test the 
workaround.

Best regards,

Laurent Pinchart
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