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Date:      Wed, 31 Aug 2005 17:03:58 +0200
From:      Bernd Walter <ticso@cicely12.cicely.de>
To:        User Tomdean <tomdean@speakeasy.org>
Cc:        ticso@cicely.de, freebsd-usb@freebsd.org
Subject:   Re: Ucom/Uftdi Thru-put
Message-ID:  <20050831150357.GD37930@cicely12.cicely.de>
In-Reply-To: <200508311442.j7VEg2Nu006607@asus.tddhome>
References:  <200508202157.j7KLv1GF005017@asus.tddhome> <20050826112422.GY37930@cicely12.cicely.de> <200508301751.j7UHpCt8000858@asus.tddhome> <200508302100.12140.hselasky@c2i.net> <200508302046.j7UKklqR000628@asus.tddhome> <20050831101526.GX37930@cicely12.cicely.de> <200508311442.j7VEg2Nu006607@asus.tddhome>

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On Wed, Aug 31, 2005 at 07:42:02AM -0700, User Tomdean wrote:
> I changed the input buffer size.  The read reported 382 bytes.  The
> buffer is 6*(4*16)==384 bytes long.  On the scope I see 6 distinct
> groupings in the USB data stream.  Looks like ucom/uftdi, or something
> up the chain, is using 64 bytes anyway.  Every 64 bytes, there seem to
> be 2 bytes not from the data stream.  Uftdi.c subtracts 2 from count,
> giving 382 bytes.

Yes - that's exactly what I'm saying: the buffer can't just be
increased without further changes.
Btw.: it is the FTDI chip itself adding the bytes.
I already said that I have tested patches to do this correctly, just
need to pic them up.

-- 
B.Walter                   BWCT                http://www.bwct.de
bernd@bwct.de                                  info@bwct.de




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