DTR / DTS vs RTS/CTS vs Wine
Mike McCormack
mikem at codeweavers.com
Wed Jul 24 16:43:27 CDT 2002
Hi Miguel,
You are correct; the Linux kernel does not support DTR/DSR flow control.
If a windows program requests DTR/DSR flow control in wine, we just
write a FIXME to stderr and ignore the setting.
Your idea to build a cable that wires the printer's DTR/DSR to the
computer's RTS/CTS may work, but you may also need some small hacks in
wine to select RTS/CTS flow control when the program asks for DTR/DSR
flow control. That won't garantuee that your program works, but it will
at least be a little better...
I guess the other option is to implement DTR/DSR flow control in the
Linux kernel... but that may not be easy :)
Mike
List vmn wrote:
> Hi,
>
> I am testing a serial printer driver that uses DTR/DTS hardware flow
> control on wine.
> While testing the driver running winedbg everything worked, not so when
> I ran the program directly from wine.
> I sent this problem to the printer manufacturer and they put a data
> scope on the serial line.
> It seems that the DTR/DTS signal was not being caught by the computer
> and therefore the computer was sending info
> over the serial port when the printer was not ready.
> I read on the net that the linux kernel does not implement DTR/DTS
> but only RTS/CTS hardware flow control.
>
> I also read that it is usual for cables to be built that connect the
> RTS/CTS pins to the DTR/DTS pins therefore tricking the computer and
> printer [the computer understands RTS/CTS and the printer DTR/DTS ] and
> getting good results.
>
> The output of --debugmsg +comm after SetCommState was called was ~IXONN
> ~IXOFF.
> Can anybody indicate that If I build the correct cable and ask for
> RTS/CTS with SetCommState , that the serial io will work?
> Any limitation of wine with RTS/CTS?
>
> Is it correct that windows does not do ANY hardware flow control?
> If so, how can this app work under windows since it only uses standard
> SetCommState, ReadFile, WriteFile calls...
>
> Thanks,
> Miguel Feitosa
>
>
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