server: Add support for pending write flag to the serial device. Take 2.

[Dmitry Timoshkov]

Wolfgang Walter <wine at stwm.de> wrote:

> I have no intention to discuss that all again. Please think about the problem. 
> Hint: writing twice as many bytes with 150 baud needs more time, significantly 
> more time then TIMEOUT.

Not really. Francois sent an investigation with pretty exhaustive explanation
of the behvaiour of COM-port UARTs regarding timings and baud rates.

-- 
Dmitry.