Re: Serial console only works after reboot?

Nate Lawson writes:
| I have a laptop (IBM T23) and use sio0 as my console/gdb port.  One thing
| I noticed is if I power up the laptop and boot -h, I get garbage out the
| serial port.  However, if I boot fully and then just warm reboot, the
| serial console works fine.  I'm only using 9600 bps.  Ideas?
| 
| sio0 port 0x3f8-0x3ff irq 4 on acpi0
| sio0: type 16550A

I use this patch on a lot of systems to force it to CONSPEED and not try
to auto-detect what the prior boot-loaders etc. had set it up.
In my case a lot of the time nothing ever set the port up and it gets
random junk the messes up the speed etc.

Index: sio.c
===================================================================
RCS file: /cvs/src/sys/dev/sio/sio.c,v
retrieving revision 1.417
diff -c -r1.417 sio.c
*** sio.c	24 Dec 2003 04:11:10 -0000	1.417
--- sio.c	5 Jan 2004 03:46:27 -0000
***************
*** 2832,2838 ****
--- 2832,2841 ----
  	/* XXX there should be more sanity checking. */
  	if (divisor == 0)
  		return (CONSPEED);
+ /* DJA
  	return (rclk / (16UL * divisor));
+ */
+ 	return (CONSPEED);
  }
  
  #endif

Doug A.