Hi,
> Hi,
>
> On Thu, Dec 19, 2013 at 02:54:31PM +0900, Anton Tikhomirov wrote:
> > > WARN_ON(ret < 0);
> > >
> > > Regards
> > > Pratyush
> >
> > By the way, chaining additional (auxiliary) TRB would allow complying
> with
> > Buffer Size Rule on _UDC_driver_level_ for any type of OUT endpoints,
> when
> > total size of a Buffer Descriptor must be a multiple of MaxPacketSize:
> >
> > rem = request_length % MaxPacketSize
> >
> > general TRB size = request_length (CHN = 1)
>
> should be request_length - rem
>
> > aux TRB size = MaxPacketSize - rem (CHN = 0)
>
> should be rem
In this case:
Buffer_Descriptor_size = general_TRB_size + aux_TRB_size =
(request_lenth - rem) + rem = request_length ,
which is not multiple of MaxPacketSize.
The idea is to build Buffer Descriptor, whose total size is multiple of
MaxPacketSize, using additional TRB.
>
> > Buffer for aux TRBs can be allocated at initialization time and used
> > when necessary.
>
> send a patch and test it for weeks ;-)
>
> --
> Balbi
Thanks
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