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Re: Plea for help from PowerMac Open Firmware gurus -- Testing new oldworld pmac miboot 2.6 floppies

On Fri, Aug 20, 2004 at 01:54:09AM -0400, Rick Thomas wrote:
> On Thursday, August 19, 2004, at 12:08 PM, Rick Thomas wrote:
> >
> >On Thursday, August 19, 2004, at 05:00 AM, Sven Luther wrote:
> >>
> >>>happy floppy disk reading noises.  However, the noises eventually
> >>>stopped and a red "X" appeared over the TuxMac. Then nothing.  I 
> >>>had to
> >>>manually eject the floppy from the drive.
> >>
> >>What we need would be a way to get a log of it or something.
> >
> >I'll try booting from open-firmware directly on a serial console.  
> >It may take a couple of trys.  I've never done that before on a 
> >Mac (On a Sun/sparc machine, it's standard operating procedure, 
> >and I've got lots of experience with Suns -- so it's not 
> >completely unexplored teritory!)  Maybe  there will be some 
> >console messages that will be helpful.
> Well... Try one gives no help.
> I booted my PowerMac 6500 with "Cmd-Opt-O-F" keys, while watching 
> the 6500's "modem" serial port on another machine running MacOS-9 
> with MacKermit at 38400 bps. I found myself talking to the Open 
> Firmware monitor on the 6500, as expected.  I was able to do a 
> couple of the exercises in Apple Tech Note 1061 ("Fundamentals of 
> Open Firmware, part I: The User Interface").  I was feeling 
> encouraged... so I typed "boot" with the floppy disk in the drive.  
> It read the floppy.  Nothing appeared on the serial console.  
> Peeking at the monitor on the 6500, all I saw there was a black 
> screen. Eventually, the floppy reading noises stopped, but still 
> nothing on the serial console and nothing on the 6500's monitor.  I 
> waited a while.  No change.

You have to give the kernel the console=ttyS1,<speed> option so the console
goes to serial log. I don't know how this is done for a miboot floppy though.

> I've been warned by someone at work that the Linux Kernel may 
> change the console's bit-rate to either 19200 or 9600 bits/sec.  
> And once the reading noises stop, it does seem that the console has 
> switched to 19200, because at that speed, things I type on it are 
> echoed coherently -- at any other speed, things I type are 
> garbled.  But all it does is echo what I type.  It does nothing 
> useful that I can see.  In particular, there are no error or 
> debug/progress messages of any kind.

See above.

> Sigh!
> Is there some kind of a boot-time parameter that one can set to 
> tell the Linux Kernel to print verbose debugging progress messages 
> on the serial console?

Yes. I do : boot vmlinuz console=ttyS01,115200n8 for example, but you would
both have to identify the actyal ttyS and the speed (19200) and the the way to
tell the kernel about that.

> While I'm asking, does anyone know how to tell the Macintosh Open 
> Firmware monitor to set the terminal speed.  I'm thinking that if 
> the Linux Kernel wants 19200, then it would be a good idea to be 
> talking to the Open Firmware at the same speed, so things don't get 
> lost in the switch-over.

Best is to adapt the linux kernel serial log to the OF set value though.


Sven Luther

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