PUC Serial I/O problem - copy of gnats-filed bug report (as discussed previously)

[Karl Denninger]

Jeremy Chadwick wrote:
> On Fri, Nov 27, 2009 at 12:54:17PM -0600, Karl Denninger wrote:
>   
>> For what its worth, USB-based serial adapters also fail in the same way,
>> but faster (they have NEVER been reliable in this regard, and this
>> hasn't improved)
>>     
>
> There must be a regression of some kind, given that some FreeBSD
> developers have stated in the past that FTDI-based USB serial adapters
> work great:
>
> http://lists.freebsd.org/pipermail/freebsd-stable/2008-March/041615.html
>
> Original thread:
>
> http://lists.freebsd.org/pipermail/freebsd-stable/2008-March/041610.html
>   
I don't know where "works great" has come from.  Certainly not my
experience in "heavy" use.

For non-modem-control heavy use, it works ok.  I use an 8-port fanout on
7.x to drive process control and it's stable.

However, for heavy modem use (e.g. Hylafax) it has NEVER been stable -
although in 8.x it won't even manage to send ONE 10-page fax most of the
time, where under 7.x it would randomly fail in that use.  Then again
the puc() driver based serial I/O was completely stable under 7.x and
now, with the "new architecture" it will get one or two jobs through it
before it blows up.

-- Karl