i386/55930: partly configured serial port freezes system

[Thorsten Kuehnemann]

>Number:         55930
>Category:       i386
>Synopsis:       partly configured serial port freezes system
>Confidential:   no
>Severity:       serious
>Priority:       low
>Responsible:    freebsd-i386
>State:          open
>Quarter:        
>Keywords:       
>Date-Required:
>Class:          sw-bug
>Submitter-Id:   current-users
>Arrival-Date:   Sun Aug 24 11:20:11 PDT 2003
>Closed-Date:
>Last-Modified:
>Originator:     Thorsten Kuehnemann
>Release:        FreeBSD 5.1-RELEASE-p2 i386
>Organization:
private
>Environment:
Booting FreeBSD while BIOS serial ports are configured to "auto"
System: FreeBSD ef80.jnx.de 5.1-RELEASE-p2 FreeBSD 5.1-RELEASE-p2 #0: Wed Aug 20 13:41:44 CEST 2003 tk at ef80.jnx.de:/home/usr/obj/home/usr/src/sys/GENERIC-DEBUG i386

	The kernel is GENERIC but the line
	"makeoptions     DEBUG=-g"
	was made active in GENERIC-DEBUG.

	Pentium1-233 on a Shuttle HOT565-Board with Award BIOS.


>Description:
	While booting the machine freezes while or right after
        displaying the loginprompt at the console.

        These are the problematic kernel messages:

	kernel: sio0: configured irq 4 not in bitmap of probed irqs 0
	kernel: sio0: port may not be enabled
	kernel: sio0 at port 0x3f8-0x3ff irq 4 flags 0x10 on isa0
	kernel: sio0: type 8250 or not responding
	kernel: sio1: configured irq 3 not in bitmap of probed irqs 0
	kernel: sio1: port may not be enabled

        In the BIOS the configuration of the serial lines was set to
        "Auto".

	
>How-To-Repeat:
	Try to boot FreeBSD with a partly or unconfigured serial ports.
	If the mentioned error messages are found, you will get a
	freeze (earlier or later).
>Fix:

        After enabling the serial ports in BIOS giving an I/O and
	IRQ the problem disappears and the kernel messages are:

	kernel: sio0 at port 0x3f8-0x3ff irq 4 flags 0x10 on isa0
	kernel: sio0: type 16550A
	kernel: sio1 at port 0x2f8-0x2ff irq 3 on isa0
	kernel: sio1: type 16550A

        You will find a dozen PR's containing the text
	      "sio0: configured irq "
	with hang or panic problems.

        I have had two different machines with the same problem
	solved by configuring the serial ports in the BIOS.
>Release-Note:
>Audit-Trail:
>Unformatted: