[sane-devel] Permission denied on parallel port Epson Expression636

[Petr Hlustik]

On Fri, Oct 04, 2002 at 07:14:27AM -0400, Karl Heinz Kremer wrote:
> Did you change anything since it worked? And I really mean anything,
> even if you think it's absolutely unreleated to scanning (e.g. 
> connect or turn on a parallel printer). I don't think that you've
> changed anything on the scanner (e.g. firmware). The scanner is 
> no longer identified with it's name because the software can no
> longer talk to the scanner ("Illegal response ...").

Karl, 

Thank you for your assurance that there is hope (no damage to
scanner). However, I tried to backtrack and undo any perturbation to the
machine HW or SW I could have made. E.g., I changed the sane.d/net.conf
entry from the actual machine name to localhost and back, I messed up with
/etc/services and /etc/xinetd.conf to allow network access (and undid the
changes).  I changed scanimage and xsane permissions to setuid root and
then back to 755 after the reported xsane Gtk+ failure. I defined (and then
undefined) SANE_DEFAULT_DEVICE='epson:0x378'. I added myself to the lp
group, which has write access to /dev/lp0 and /dev/parport0 and removed
myself again later. I ran "strace xsane epson:0x378 >& strace.xsane"
repeatedly to find the write permission problem and watch whether it would
go away with any of my manipulations. One of my craziest actions was to
"echo '0' > /dev/lp0" to see whether I truly have write permission to that
device (before I fully realized that sane does not use the devices).  I
also powered the box down and did a cold reboot to no effect. 

If I have not messed up the scanner, could I have messed up the parallel
port controller? I don't have a printer available here to test the parallel
port with something else.

Well, after I've written all this, I remembered I brought in my Debian
Sarge laptop - so I installed sane there and tried the scanner there after
modyfing the sane.d/epson.conf. I ran sudo xsane just fine. I guess I did
mess up the parallel port on my desktop box after all. :-(

Thank you again for your help. 

Best,
Petr