[sane-devel] Plustek 9636T memory test failure

[Oskar Schirmer]

Hi Gerhard,

On Thu, Sep 09, 2010 at 08:15:02 +0200, Gerhard Jaeger wrote:
> Am Dienstag, 7. September 2010, 12:29:07 schrieb Oskar Schirmer:
> > Trying to get the plustek 9636T work
> > on an Ubuntu 10.04 500MHz x86 installation,
> > but it fails during detection. With
> > export SANE_DEBUG_PLUSTEK_PP=255 set,
> > scanimage run with root permissions says:
[...]
> > What's going wrong,
> > what does the memory test and IODELAY thing tell?
> 
> during startup the driver tries to connect to the scanner
> and to detect the type - seems this works. Next step
> is to checkec wether data can be written to and retrieved
> from the scanner. This fails. This test (ioP98ReadWriteTest()),
> tries that with several delay settings. It turned out,
> that it's not always possible to access the device 
> as fast as possible and that's why there's an IODELAY setting.
> 
> In your case it's not possible to access the memory,
> that's why the procedure fails. You might check the BIOS
> settings for the parallel port, play with the modes.
> Try different settings (SPP, EPP)

I found it does work when CONFIG_PARPORT_1284 is
disabled in the kernel (Ubuntu has myriads of modules
around and it seems they load everything that doesnt
explicitely fail probing).

Now I am trying to scan slides, with transparency mode.
Scanning a slide 150 dpi takes quite long, some 65 seconds.

It works with 150 dpi (which does not make much sense
for 24x36mm slides), apart from the fact that transmission
is incomplete (last some 1000 bytes missing) and scanimage
finally hangs. The command I use is:
scanimage --source Transparency --resolution 150 --contrast 100% -l 0 -t 0 -x 43 -y 44

The last lines it says before hanging are:
...
[plustek_pp] Moving 32 bytes to scanner, IODELAY = 0...
[plustek_pp] ... done.
[plustek_pp] Moving 32 bytes to scanner, IODELAY = 0...
[plustek_pp] ... done.
[plustek_pp] sending 189738 bytes to parent
[plustek_pp] sane_read - read 32768 bytes
[plustek_pp] sane_read - read 32768 bytes
[plustek_pp] sane_read - read 32768 bytes
[plustek_pp] sane_read - read 32768 bytes
[plustek_pp] reader_process: finished reading data
[plustek_pp] sane_read - read 32768 bytes
[plustek_pp] sane_read - read 25898 bytes


For 300 dpi it fails to get the aspect ratio right
(as the man page sane-plustek_pp(5) describes it).

When trying 600 or 1200 dpi, the scanner starts to work
like with lower resolution but ends up moving the carriage
forth and back infinitely in a small range, and repeats
itself in saying "Moving 32 bytes" etc.

Is 600 and/or 1200 dpi known to work with transparancy?
If so, how could I get a hires picture out of that box?

thanks a lot,
  Oskar