apm power_off hangs system
After 8 years of running Debian, I've never had Linux crash on me
before, not once! Until now that is...
I've just upgraded my wife's PC from OS/2 to Woody. No real problems,
other than I found it a bit tricky getting X 4.3 installed, so that I
could use the GLX drivers for her nVidia GeForce2 video card. But thanks
to http://people.debian.org/~mmagallo/ for sorting that out, now it's
all installed OK and running nicely.
I sold the idea of going over to Linux by booting the Knoppix CD, and
showing off OpenOffice.org, and all the great stuff that's on that CD.
One of the nice things that Knoppix does is to turn the computer right
off when you shut down Linux. My wife wanted this functionality, so I
thought I had better start brushing up on apm.
I added the required line:
append="apm=on apm=power-off"
... in etc/lilo.conf, and ran lilo OK
I also added the single line:
apm power_off=1
...to /etc/modules, then rebooted the system. No problems logging in,
lsmod showed that apm was loaded, so time to try this thing out!
I logged out of Gnome, expecting to get back to the gdm login greeter
(which I have set up to show the shutdown menu). The screen first went
blank, as it usually does when the nVidia driver restarts itself, but
instead of the nVidia splash screen, it came back with a pastel-coloured
screen with a one-centimetre horizontal stripe across the middle. At
this point the whole system was hard locked - no keys worked, I couldn't
get to a console, nothing! I hadn't seen this kind of behaviour since my
Windoze NT days! I pressed the hard reset switch and thanked my stars
that I had chosen ext3 as the filesystem, so that fsck could run a bit
more swiftly.
OK, time to chase this one down! I had only changed two things (the two
lines mentioned above), so start by removing them, running lilo,
rebooting and checking that all is well. No problem. I then added the
/etc/lilo.conf line, ran lilo and rebooted (wow, 4 reboots in one day -
more shades of Windoze). No problems there, OK to log out back to the
greeter, log back in again, switch to virtual terminal and back to
Gnome. So the problem must lie in the apm module itself, or it's
interraction with some other part of the system.
Next, _don't_ modify /etc/modules, just load the thing manually with this:
# modprobe apm power_off=1
... and check that it is loaded with lsmod - no problem. Time to log out
again, but first be a bit sneaky and do a quick sync, as I expect things
to go belly-up again. Sure enough, same problem as before, Crash!. Hard
reset, fsck, log in again. What next?
Maybe this is a problem between apm and the video driver? Load the apm
module and do a <Ctrl><Alt><F1>. Yep, that breaks it.
Now I don't know what to try, other than see if I can just load and
unload the apm module. So after next reboot:
# modprobe apm power_off=1
# rmmod apm
Crash!
So now, I am stumped :-( . Other than a vague feeling that this has to
do with the nVidia driver, I really don't know what to try next. Any
ideas anyone?
--
Cheers,
.~.
/V\
// \\
/( )\
^`~´^
< hugge >
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