Comment 9 for bug 46445

I know it's been a few years and considering that Canonical dumped PPC, this probably isn't being worked upon. Gad, I assume as much as this bug has been around 2006. I'm writing this in 2009. The only real chance of it being solved is reporting it to Debian, which has never stopped supporting PPC, officially or otherwise. I'll report it to Debian and post a copy of this to my blog for reference to other PPC users. For reference, I had this problem with Jaunty (Ubuntu-PPC) and have it with Lenny (Debian).

UPDATE: I've done a bit of research and this is what I've thought it could be, although no machead in #macosx (at least, when I've asked) dares hypothesize or cares. I did not consider that pbbuttonsd was causing the problem because I don't have it installed.

1. Could be a dead or dying battery. Fix: replace it.
2. Could be corrupt firmware, on the off chance --although I don't quite see how. Fix: start up command(open apple key)+opt+p+r and hold till you hear 3 chimes. This will reset the internal clock (which supposedly will need updating) --among other things. I hope you set your OS to use external clock settings and not the open firmware ones.
3. Jammed power button. Fix: make sure it pops out (ease it with your finger) at boot up.

Now for the deductive (or inductive) part. Since this problem didn't present itself with OS X, which I recently had installed, it isn't a firmware, battery issue, or a jammed power button (especially since I've checked them and verified they pop out when powering up).

Still, I reset the pram settings just in case they were at fault. This doesn't change the behavior. In fact, what does is unplugging the USB keyboard immediately after issuing shutdown.

Earlier, I thought it might NOT have been the keyboard because the problem inconsistently presented itself --with it and without it plugged in. I thought it had to do with from where the shutdown routine had originated (X11 or not) and maybe had to do with the type of shutdown command issued, "halt" or "shutdown -h now". I had better luck with "shutdown -h now". I've had the unwanted automatic reboot enough times with both the command and X11 environments to know it has nothing to do with the type of shutdown command issued or the environment origin.

Work around #1
So, I've been unplugging my keyboard immediately after issuing a shutdown and it works faithfully. That is, until I started to leave a USB audio device --which is picked up as a sound card by alsamixergui-- plugged in. at first, I thought back to square one. It isn't my keyboard. But then I thought, could it be my keyboard and my newly introduced external gadget? A certain Niel that posted on an Apple discussion thread thinks so (some OS X users have been having the same issue).

"Some external USB devices send out a boot signal;"

His work around consists of,
"... placing a self-powered USB hub between your computer and the device will filter out boot signals."
http://discussions.apple.com/thread.jspa?messageID=5034481

Notice that there is not mention of "timings" and that the Apple thread demonstrates that users of Apple's OS do (sometimes) have this problem.

Work around #2
So that's another work around. But it necessitates buying a powered USB hub. I have one, I just got to find the matching power supply. This leaves one possible last work around.

Work around #3:
I remember Debian Woody shutdown procedure. After the OS went through the shutdown routine, one had to physically press the power button to cut the power. I imagine hacking the shutdown routine to omit cutting power portion might be a doable and temporary work around --if not a real solution. I have no idea on how to do this, but if someone could post a HowTo or if I find out, I'll write it up.

Still, the problem should be solvable via software as I remember Debian Sarge, Yellow Dog, and Mandrake did not have this problem --nor does OS X in general.

Solution:
Of course the ultimate solution would be to fix the OS so as to ignore what it might be interpreted as startup commands on shutdown.

Thoughts:
Since I don't have pbbuttonsd installed and I still have this problem, this bug is not a duplicate of Bug 57069 (Ubuntu).