[sane-devel] Erratic problems with saned/xsane

[Henning Meier-Geinitz]

Hi,

On Sat, Dec 07, 2002 at 12:14:37PM -0300, John Coppens wrote:
> > I have never tried that but you could play with permissions of the
> > epson.conf file and/or libsane-epson.so.version. Setting them so only
> > saned can load the backend may work.
> 
> Ok. I'll try that this afternoon - the PC is at the Foundation, so I
> can't do it right now. Could the double access (xsane -> parallel port,
> and saned -> parallel port) have something to do with the erratic
> behaviour?

I don't think so because you don't have access to the parport as
normal user anywway.

But to avoid disturbance from other backends, comment out everything
but net and epson in dll.conf.

> > Another way would be to link xsane to the net backend directly,
> > without using libsane-dll.
> 
> Don't know how to do that... But I'll have a look. It would be easier
> to use afterwards, I think.

For testing: LD_PRELOAD=/usr/local/lib/sane/libsane-net.so xsane &
Otherwise when you run make in the xsane distribution, look for the
final linking command

> For example: Xsane comes up in Binary Mode (1bit), I try to change to
> color or gray and get the 'invalid parameters' error. Yes, I can still
> give the order to scan, for example. And even though the error was
> signalled, the menu now shows Color or Gray. The scanner scans Binary.
> 
> Sometimes, it's the scan command that fails with the same message. It's
> as if the backend doesn't relay the capabilities reliably to the xsane
> frontend. Could this be a reliability issue for the comm thru the parallel
> port? Or are these exchanges checksummed & tested?

I don't think so because you would see the errors wwith xsane as root
in this case, too.

Either it's really a saned/net issue or a problem of the epson backend
that only occurs in conncetion with saned/net. The latter thing has
occured some times, saned/net is a bug-finder :-)

> > > All versions are the last ones - fresly downloaded. Kernel is 2.4.18,
> > > and the scanner is an Epson ActionScanner II (GT-5000M). All points
> > > to unreliable comm between xsane and saned...
> > 
> > The communication flow is like this:
> > 
> > xsane <- linking -> libsane-dll <- dynamic loading -> libsane-net <- network
> > network -> saned <- linking -> libsane-dll <- dynamic loading -> libsane-epson
> 
> No wonder someone gets confused ;-)
> BTW, I'm not scanning over a network. I use 'localhost' here.

That's network, too :-) net connects to saned over tcp. From the SANE
point of view it doesn't matter if it's localhost.

> Will do all that - but I guess it will be long. Shall I send it 
> personal?

If they are longer than 10 kb (compressed), send them to me
personally.

Bye,
  Henning