Re: PPMC progress

[Ray <rehenry-at-up.net>]

On Sun, 10 Dec 2000,  Jon wrote:
> I now have all 3 axes that are supported in my versions of EMC
> working from encoder input to DAC output.

Good News.  I'd like to show one running something at NAMES.  Let's talk
off list about this.

> The crashing problem I had is actually an old one, having
> something to do with either Linux 2.0.36 or the RT patch
> and the TkEMC GUI.  I have had a number of versions
> of EMC later than 15-Mar-2000 that would hang up the
> XFree86 screen, keyboard and mouse, or the whole
> system.  I tried running the xemc GUI instead of TkEMC,
> and it continued to work for about 45 minutes, until I
> glitched the hardware with an errant scope probe.
> Ray, do you have any ideas about this?  I'd much
> prefer to stay with the TkEMC, but if it will only work
> with 1999 releases of EMC, that is kind of limiting.

Yes, and I was using a 99 release at NAMES last year and got the same kind
of lock up a couple times.

Ho! Wah! (a youpperism who's meaning varries greatly with the inflection
used to express it.)  And it seems to get worse with the tcl lib that I've
been building.  I thought that it might be related to the problems with
mbuff but if you have increased the problems with your additions to 2.0.36
then it is more fundamental than that.

I have a very had time believing that Tcl/Tk all by itself can reach in
and trash the mouse and keyboard IO.  There must be some overlap between
the EMC code, the tcl interpreter, emcsh, and the commands being passed
from one end of the programming stack to the other.   

Another thing that I have noticed, but this is not a hard empirical
conclusion is that a newly installed EMC does it less frequently than does
a used system.  Go ahead and laugh and flame but the software seems to
degrade over many starts.  With the lib work, I've had to reinstall the
9-25 bin at least three times or after a few dozen starts, it will hardly
run cds.ngc at all. 

I thought for a while that the problem was that when the EMC shut down, it
left some garbage around.  It will often leave mbuff in the core but that
is only a post 2.0.37 problem.  Rebooting seems to help some but after a
bunch of starts and stops, it gets almost impossible to work with.  Almost
as irritating as BSOD.  I haven't reinstalled the rtlinux only the EMC.

My plan was to reinstall everything from Mandrake on but I'd like to get
to the bottom of the real problem rather than just getting a new run at
it.  Since I have a "cripple" here, I'd like us to study it.  But I have no
clue what to do next.  

Could someone help with a debug routine that traces the whole system
through.  I could run it here and post the results for study. Will tried a
while back with the mbuff problem but I found no real clues from all of
what he suggested.   As Jon points out below, any debug routine would have
to save to a fifo during the run 'cause there is no good way back into the
kernel.  Maybe a network, and I could set up one of those.

> (I still have the debugging stuff you sent me in June, 2000,
> but I'm not too sure what good it will do, as the lockups
> kill the keyboard and mouse.  The caps lock key no longer
> toggles the caps lock light, and the Ctrl/Alt/Backspace
> won't kill X.)

Thanks in advance for your help.
-- 

Ray