OFW access from linux

Paul Fox pgf at laptop.org
Tue Sep 15 17:31:52 EDT 2009

john wrote:
 > > there's no SysRq key on the XO keyboard, so you'll need to use a
 > > break on the serial console to invoke it...
 > Please.  If you're going to put this hook in, which I think is a great
 > idea, at least make it work on the standard hardware!  And when the
 > operating system is not very responsive.  That's when you'll need it
 > for debugging or resetting the system.  Without taking the plastic
 > apart, finding a part with no known suppliers, and soldering it to
 > your motherboard.

i agree.  getting the hook in place was a first step, and
satisfies my immediate need for wanting to be able to look at and
modify h/w registers during development -- the /proc trigger
is sufficient for that.  we have a constant tension between "just
make it work on the XO" and "make it so we have a prayer of
merging it upstream without lots of pushback", and i confess i
erred towards the latter, this time.  custom key combinations
would require more extensive changes to the input drivers than i
was willing to take on last night.

 > On Sun workstations, the "L1-A" key combination (pressed in exactly
 > that order, with no intervening keys or key-ups) got you into OFW or
 > its predecessor.  (L1 was the top left key in the keypad to the left
 > of the main keyboard.)  We shipped it that way for decades without
 > trouble.

as i recall, unplugging the keyboard was the more frequent, and usually
accidental, means of invocation.  at least in my case.  :-)

 > There are some pretty obscure keys on the XO keyboard -- howabout
 > something like holding down the leftmost and rightmost "gradually
 > increasing sized dots" keys in the top row, and then pressing the
 > M-for-Mitch key?

i would applaud, encourage, and otherwise buy beer for anyone that
could help out in making something like this happen.  (i might get
to it someday, myself, but that will no doubt be _after_ i need it.)

 paul fox, pgf at laptop.org

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