>>>>> "Andrew" == Andrew Worsley <amworsley@xxxxxxxxx> writes:
Andrew> ftdi_set_termios() is always setting the baud rate and data bits
Andrew> and parity on every call. When called while characters are being
Andrew> transmitted can cause the FTDI chip to corrupt the serial port
Andrew> bit stream by stalling the output half a bit during the output
Andrew> of a character. Simple fix by skipping this setting if the baud
Andrew> rate/data bits/parity are unchanged.
Andrew> Signed-off-by: Andrew Worsley <amworsley@xxxxxxxxx> ----
Andrew> This bug was observed on 2.6.32 kernel (this patch is ported to
Andrew> latest kernel for ease of review). Using a FTDI USB serial chip
Andrew> at 38400 repeatedly generating output by running a simple
Andrew> command such as "uname -a" or "echo Linux" gives occasional
Andrew> corruption on the output
Andrew> ...
>> echo Linux
Andrew> L$,3u=(Bnux
Could you please give a more specific receipe to reproduce the bug. Running
with an adapter with TX/RX shorted at "stty -F /dev/ttyUSB0" 38400", several
> uname -a /dev/ttyUSB0
runs gave no artifact in a "seyon -modem /dev/ttyUSB0" console.
Doing
> uname -a /dev/ttyUSB0
in one xterm and receiving with
>cat /dev/ttyUSB0
in another xterm gives lot of repeated lines in the receiving terminal. But
I have the same behaviour with /dev/ttyS0 on a real serial port on the
mainboard.
Otherwise, shouldn't all control transfers to the FTDI be only done with the
tx buffer in the FTDI empty? I guess the RX buffer is not affected by some
change. But this is something to be done with great knowledge...
Bye
--
Uwe Bonnes bon@xxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxxx
Institut fuer Kernphysik Schlossgartenstrasse 9 64289 Darmstadt
--------- Tel. 06151 162516 -------- Fax. 06151 164321 ----------
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