serial console speed

[Danny Braniss]

> On Thu, Jul 03, 2008 at 05:34:27PM +0300, Danny Braniss wrote:
> > > On Thu, Jul 03, 2008 at 03:21:14PM +0300, Danny Braniss wrote:
> > > > it seems that there is no way to change the speed/baudrate of the serial
> > > > console, for example, by turning it off in /etc/ttys, and running
> > > > tip(1) with different speeds has no effect, it always
> > > > stays at the kernel configured speed.
> > > > 
> > > > is this by design?
> > > 
> > > Yes.
> > 
> > why?
> > 
> > to add some more 'issues', setting 
> > 	hint.sio.1.flags="0x10"
> > does the redirection correctly but does not fix the speed to CONSPEED, and
> > stays at 9600. (BTW, this used to work).
> 
> The 9600 limitation is out-of-the-box.  Despite what may seem logical,
> in my experiences the console serial port speed on FreeBSD is "limited"
> to a maximum of 9600bps unless you either use the -S flag in
> /boot.config (e.g. -S115200), or loader.conf variables to adjust the
> speed.
> 
> Others will have to answer your remaining questions.
> 
> > setting the serial speed means,
> > 	compiling correctly btx, pxeboot, kernel, ilo.
> > now it seems that any info in /boot.config or /boot/loader.conf is also
> > ignored.
> 
> This part is flat out incorrect.  You no longer have to rebuild
> anything, you can simply place -S115200 in /boot.config and it will
> work.  I know, because every single one of our production servers
> (RELENG_6 through RELENG_7) use this.  We **do not** rebuild boot
> blocks.
ok, need some explanation/rational:
	when booting via pxeboot, initialy, the BMX & libi386 have the serial 
port/speed
hardcoded (for good reason), and as soon as posible it gets 'corrected' via 
the configuration files.
things get complicated when the bios is uncooperative - e.g: Sunfire X2200/ilo.
then, as if by magic, a bios upgrade solved most of the problems!
- ofcource, the bios upgrade was triggered by another problem - why is
PowerNow! not recognized :-(

Oh, btw, you can change the serial speed of the console:
	sysctl machdep.conspeed=115200
which was the initial question :-).

> 
> Please read this document for my findings.
> 
> http://jdc.parodius.com/freebsd/pxeboot_serial_install.html
> 
> -- 
> | Jeremy Chadwick                                jdc at parodius.com |
> | Parodius Networking                       http://www.parodius.com/ |
> | UNIX Systems Administrator                  Mountain View, CA, USA |
> | Making life hard for others since 1977.              PGP: 4BD6C0CB |
>