Path: utzoo!mnetor!uunet!husc6!bloom-beacon!gatech!galbp!bing
From: bing@galbp.LBP.HARRIS.COM (Bing Bang)
Newsgroups: comp.os.minix
Subject: Re: Problems with serial TTY driver
Message-ID: <3094@galbp.LBP.HARRIS.COM>
Date: 18 Dec 87 18:38:45 GMT
References: <2314@encore.UUCP>
Reply-To: bing@galbp.UUCP (Bing Bang)
Organization: Harris/Lanier, Atlanta, GA
Lines: 27

In article <2314@encore.UUCP> paradis@encore.UUCP (Jim Paradis) writes:
>After many weeks of not quite being able to get around to it,
>I finally added serial line support to my rewritten MINIX TTY
>driver.  It works, but there's one serious problem: If I test
>it out by looping back transmit and receive on the serial line
>and running a quick&dirty terminal program, if I type at it
>too fast the system will hang.  Now, I remember someone else in
>this newsgroup sometime back who added serial capabilities to
>the stock TTY driver and ended up with the same problem.  Is there

well, i'm glad i'm not the only one having this problem. i've been trying
to track this problem down for months. maybe we can team up. here's what
i know of the problem. in tty_task, the message structure tty_mess is
declared so that it is allocated on the stack. the problem seems to be that
some routine corrupts 6 or 8 bytes just below the address of the structure.
this of course usually contains the reuturn address and stuff from the
receive() call tty_task makes. i know the corruption is relative to the
structure address becuse i can make other declarations in tty_task to move
the location of the structure. the problem can be "solved" by allocating
a char array just below the structure, although memory in the array still
get corrupted. i do not care for this solution.


-- 
Bing H. Bang           +----------------------------------------------------+
Harris/Lanier          |MSDOS and OS/2 (whenever it gets here): just say no.|
Atlanta GA             +----------------------------------------------------+