serial port fix ??

[Jon Jenkins]

The Intel based Pentium mother boards
have a well known bug in the serial port.
Microsoft and Intel have both published
fixes for this problem (if you have those
I would appreciate an ftp pointer to them ??)

I have recently also noted the same problem
with SLIP and FreeBSD. The problem is something
to do with the FIFO becoming stuck when the
serial port is accessed for the SECOND time.
Does anyone know the following:

a) exactly what the problem is ?

b) how Intel/Microsoft fix the problem ?

c) is there a fix either in the "current" BSD serial driver
or a pacth available ?

Thanks

--
----------------------------------------------------------------------
Name: Dr Jon Jenkins
Location: Digital Equipment Corp, NaC,
Burnett Place, Research Park,
Bond University, Gold Coast
QLD, AUSTRALIA 4229
Phone: 61-75-75-0151
Fax: 61-75-75-0100
Internet: jenk...@ozy.dec.com
Close Proximity: "HEY YOU !!!"

The opinions expressed above are entirely personal and do not
reflect the corporate policy of DEC or the opinions of DEC management.
-----------------------------------------------------------------------

[steven ratliff]

Jon Jenkins (jenk...@oils.ozy.dec.com) wrote:
: The Intel based Pentium mother boards

: have a well known bug in the serial port.
: Microsoft and Intel have both published
: fixes for this problem (if you have those
: I would appreciate an ftp pointer to them ??)

: I have recently also noted the same problem
: with SLIP and FreeBSD. The problem is something
: to do with the FIFO becoming stuck when the
: serial port is accessed for the SECOND time.
: Does anyone know the following:

: a) exactly what the problem is ?

: b) how Intel/Microsoft fix the problem ?

: c) is there a fix either in the "current" BSD serial driver
: or a pacth available ?

There was a patch for this posted to the net way back in May or June
of last year. It was a very simple one liner if I remember correctly that
simply did an inb() on the uart before enabling the fifo. I kinda thought
that it was pulled into 1.1.5.1 and 2.0 and later versions of FreeBSD already.

Steve

[Nate Williams]

In article <1995Apr6.0...@news.csuohio.edu>,

steven ratliff <stra...@cis.csuohio.edu> wrote:
>Jon Jenkins (jenk...@oils.ozy.dec.com) wrote:
>: The Intel based Pentium mother boards
>: have a well known bug in the serial port.
>: Microsoft and Intel have both published
>: fixes for this problem (if you have those
>: I would appreciate an ftp pointer to them ??)
>
>: I have recently also noted the same problem
>: with SLIP and FreeBSD. The problem is something
>: to do with the FIFO becoming stuck when the
>: serial port is accessed for the SECOND time.
>: Does anyone know the following:
>
>: a) exactly what the problem is ?

The problem is caused by the new UART's not being fully 16550A compatible.

>: c) is there a fix either in the "current" BSD serial driver
>: or a pacth available ?

FreeBSD 2.0 and up has the fix available, and I believe a patch to 1.1.5
is available for this on ref.tfs.com.

Nate
--
na...@FreeBSD.org | Do you think SRI cares what I say? They certainly
na...@sneezy.sri.com | don't accept responsibility for my actions, so I
work #: (406) 449-7662 | obviously don't represent them on Usenet.
home #: (406) 443-7063 | *FreeBSD core member and all around tech. weenie*