misc/141655: Serial Console failure on Dell servers

[Jonathan Call]

>Number:         141655
>Category:       misc
>Synopsis:       Serial Console failure on Dell servers
>Confidential:   no
>Severity:       serious
>Priority:       high
>Responsible:    freebsd-bugs
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Tue Dec 15 20:50:01 UTC 2009
>Closed-Date:
>Last-Modified:
>Originator:     Jonathan Call
>Release:        FreeBSD 7.2
>Organization:
>Environment:
FreeBSD eng20.newthk02.hk.mycompany.net 7.2-RELEASE-p4 FreeBSD 7.2-RELEASE-p4 #1: Tue Oct 13 03:50:52 UTC 2009     root at master1.mycompany.net:/usr/obj/usr/src/sys/ENG0  i386

FreeBSD eng0.newthk02.hk.mycompany.net 7.2-RELEASE-p4 FreeBSD 7.2-RELEASE-p4 #0: Fri Oct 16 17:54:50 UTC 2009     root at eng0.newthk02.hk.mycompany.net:/usr/obj/usr/src/sys/ENG0  amd64
>Description:
Tty/login access on the serial console of Dell models 2950 and R710 stops working immediately after a single login session over the console. Sending a <ctrl-d> seems to temporarily resolve the issue long enough to log in, but the issue will immediately return once the session is ended.



>How-To-Repeat:
Configure a Dell 2950 or R710 with FreeBSD 7.2 for serial console using the Handbook instructions.
Reboot the server.
Log in using the serial console.
Log out.
The serial console will stop responding until you hit <ctrl-d>.
>Fix:
I found this on the Internet and I tried it. It worked in our lab:

*** /usr/src/sys/dev/sio/sio.c  Wed Apr 15 03:14:26 2009
--- sio.c       Tue Dec 15 20:31:48 2009
***************
*** 2077,2086 ****
--- 2077,2087 ----
  
        com = tp->t_sc;
        if (com == NULL || com->gone)
                return;
        mtx_lock_spin(&sio_lock);
+         DELAY(250000);
        if (rw & FWRITE) {
                if (com->hasfifo)
  #ifdef COM_ESP
                    /* XXX avoid h/w bug. */
                    if (!com->esp)



>Release-Note:
>Audit-Trail:
>Unformatted: