Re: [hpoj-devel] Sane owner?

[Obi-Wan <bv...@in...>]

I didn't mean to rush you with my tiny little problems.  I just didn't
want to have gotten kicked off the list or be dumping it due to a
typo in a mail filter or something.

>> I also had sane lock up on me while scanning.  I was getting a preview
>> scan of the entire bed after putting in a new photo.  It had scanned
>> almost the entire thing, when it just stopped.  XSane wouldn't refresh
>> its windows.  There were no syslog messages & nothing to 
>> stdout/stderr.
>> After a minute or two, the scanner light returned to home, but still
>> no refresh from xsane.
>
> If the lockup happened right when the cron job started, then I suspect it's
> more than coincidence, because ptal-mlcd does its parallel-port signalling
> in user mode and could theoretically be affected if it's starved for CPU
> time.  If this happens again, it would be helpful if you could attach gdb to
> the running(?) ptal-mlcd process and get a stack trace ("bt" I think) to see
> what it's blocked on.  Note that when you attach gdb to a running process
> like this, the process will be suspended until you exit gdb or issue the
> "continue" (I think) command.

OK, I duplicated it.  It happens after I successfully scan one photo.
When I want to scan another photo at a different orientation (horz vs
vert), I hit the magnifier-undo, then the magnifier-minus (zoom out),
then hit "acquire preview".  It scans virtually the entire image, then
locks up xsane.  After a few minutes, the PSC makes a noise, then prints
the LCD message "Power system failure.  Turn power off then on again."
Still no response from xsane.  No cron jobs this time.  The stack trace
isn't very useful, since it wasn't compiled with -g.

tatooine:/usr/local/build/hpoj/mlcd# gdb ptal-mlcd 25968
GNU gdb 5.0
Copyright 2000 Free Software Foundation, Inc.
GDB is free software, covered by the GNU General Public License, and you are
welcome to change it and/or distribute copies of it under certain conditions.
Type "show copying" to see the conditions.
There is absolutely no warranty for GDB.  Type "show warranty" for details.
This GDB was configured as "i686-pc-linux-gnu"...
/usr/local/build/hpoj/mlcd/25968: No such file or directory.
Attaching to program: /usr/local/build/hpoj/mlcd/ptal-mlcd, Pid 25968
Reading symbols from /usr/lib/libstdc++-libc6.2-2.so.3...done.
Loaded symbols for /usr/lib/libstdc++-libc6.2-2.so.3
Reading symbols from /lib/libm.so.6...done.
Loaded symbols for /lib/libm.so.6
Reading symbols from /lib/libc.so.6...done.
Loaded symbols for /lib/libc.so.6
Reading symbols from /lib/ld-linux.so.2...done.
Loaded symbols for /lib/ld-linux.so.2
0x40150c3e in select () from /lib/libc.so.6
(gdb) where
#0  0x40150c3e in select () from /lib/libc.so.6
#1  0x0 in ?? ()
(gdb) quit
The program is running.  Quit anyway (and detach it)? (y or n) y
Detaching from program: /usr/local/build/hpoj/mlcd/ptal-mlcd, Pid 25968
tatooine:/usr/local/build/hpoj/mlcd# psg ptal
root     25968  0.1  0.6  1824  204 pts/3    S    Jun20   6:42 /usr/local/sbin/ptal-mlcd par:psc500
root     25970  0.0  0.0  1260    0 pts/3    SW   Jun20   0:00 [ptal-printd]

Power cycling the PSC seems to be the only thing necessary to fix
the problem.  I didn't have to restart xsane or ptal-mlcd, and it
started working again.

Upon revival, the rulers are off again.  The numbers along the top
are exactly double the numbers along the left.

> I've thought about that, but the problem is that there may be situations,
> such as a "kill -9", where it's not possible to log a message.  ptal-mlcd
> logs a message when it hits a "fatal error", so the only remaining
> situations I can think of without a log message are where it segfaults or
> you kill it.

Good point.

>> Upon restarting xsane, I see that the vertical ruler is now correct.
>> Hmmm...
>
> Perhaps the peripheral got confused and power cycling it got it back in a
> good state.  Do you remember what you had been doing before this problem
> happened?

Are these ruler numbers dependent on info reported by the device?
Is this what happens when it reports a different vertical vs horizontal
resolution, for instance?

-- 
Ben "Obi-Wan" Hollingsworth                             ob...@je...
   The stuff of earth competes for the allegiance I owe only to the
     Giver of all good things, so if I stand, let me stand on the
       promise that You will pull me through.  -- Rich Mullins