FW: Looking for basic documentation on Cygwin and Serial Ports

Dave Korn dave.korn@artimi.com
Sat Apr 26 12:37:00 GMT 2008


Charles Wilson wrote on 25 April 2008 18:16:

[ Thread duely TITTTL'd ]

> Dave Korn wrote:
> 
>>   AAAARGH[*]!  FTDIchip are the bane of my life at the moment.  Buggy
>> drivers. I hate them so much <spit>. 
>> 
>> [*] - I just got back from rebooting a testrig that locked up due to
>> buggy ftdichip drivers at about the twentytwo-hour point into a
>> twentyseven-hour testrun.  I am not happy.
> 
> Wow. I've been using them too, but have had no problems at all
> (WinXPsp2) from native consoles (no cygwin involved, if that matters).
> Then again, I wasn't trying to run 27 hour tests.

  The unplug-while-you-still-have-a-handle-open thing is fairly reproducible.
Device stays busy and can't recover; the COM port can't be opened again until
you reboot.

  As to the lock up crash, I think that it's just a rare-enough race condition
that you wouldn't expect to see it except once in (quite a lot of traffic)
times.  It's a bad one, though: the screen goes black and the PC stops
responding, as if it had dropped into a standby or hibernate state.  Except
that it doesn't respond to anything you do to try and wake it, including
hitting the soft power button, pressing keys or moving the mouse, and plugging
or unplugging USB devices (which sometimes helps flush through the system when
its gone wrong by triggering interrupts and other IO activity).

  Another issue is that there are an awful lot of devices such as bus
analyzers and fpga programmers and so on that all use FTDIchip devices
internally, and all the manufacturers ship their own lightly-customised
variants of the FTDIchip drivers, many of which are out-dated or immature
versions, and the different drivers all stomp on each other trying to claim
the same VID/PID combinations.

  Oh, and they appear to be none too reliable downstream of hubs either.


    cheers,
      DaveK
-- 
Can't think of a witty .sigline today....



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