Re: ppSCSI and Microtek Phantom 330 CX

Camille DIOU (diou@lirmm.fr)
22 Sep 1999 13:53:02 +0200

Hi Bernd,

* "BS" == Bernd Schroeder écrivait le Wed, 22 Sep 1999 12:37:13 +0200:

onscsi.1: Arbitration failure, bs=31 cb=0 [...cut...]

BS> Even if the 'no-backtrack-option' is set it is possible that
BS> the scanner stops and starts, but should not move back. Here it
BS> looks as if one or more buffers are read, but then the device
BS> fails to read another buffer. I don't know what the error
BS> messages mean, but it looks like a problem with the ppSCSI
BS> stuff. Maybe you should ask on the linux-parport mailinglist.

The 'arbitration failure' error message also arise when I turn off the
scanner while scanning. Maybe a communication problem between the
module and the hardware. I'll try the parport mailing-list.

I forgot something: scanimage seems to work with lineart mode.

>> Is there any way to avoid the head hitting the borders of the
>> scanner? (I didn't find any solution in the archive since Juny).

BS> For some reason the device doesn't find the zero position. I
BS> think that if a preview scan is done it tries to scan an A4
BS> sized image, but because a number of lines are missing at the
BS> beginning it tries to scan beyond the bottom of the scan
BS> area. If this is the case it should at least work better, if
BS> you do a normal scan, but don't specify the whole scan area.

That's right.

BS> There is one SCSI command that sets all the parameters for a
BS> scan - including the scan area - and these are set correctly,
BS> so it should start at position 0.

I tried the -t -b -x -y options to define the scan area without
success. I got an error message concerning the --br-c (sorry but I
don't remember it exactly).

BS> One thing you can try is: Set the still experimental and
BS> undocumented 'option backend-calibration on' in the
BS> microtek2.conf file, if it exists in your version. Otherwise
BS> download a newer version from
BS> ftp://ftp.muc.de/people/bernds/mtek2.

I'll try that.

BS> If this option is set this will enable an additional option in
BS> the frontend (Calibration by backend). If this option is
BS> checked the backend instead of the device will do a colour
BS> calibration at the beginning of a scan. This will involve some
BS> additional commands to position the scan head. I don't know if
BS> it helps, but I think it's worth a try.

BS> When the scan head returns to its home position after a scan
BS> the backend it not involved at all. After the last buffer has
BS> been read the head moves back automatically, and there is no
BS> command to position it.

I tested the scanner with the -T option. What I got is:

scanimage: scanning image of size 612x838 pixels at 24 bits/pixel
scanimage: acquiring RGB frame, 8 bits/sample
scanimage: reading one scanline, 1836 bytes... PASS
scanimage: reading one byte... PASS
scanimage: stepped read, 2 bytes... PASS
scanimage: stepped read, 4 bytes... PASS
scanimage: stepped read, 8 bytes... PASS
scanimage: stepped read, 16 bytes... PASS
scanimage: stepped read, 32 bytes... PASS
scanimage: stepped read, 64 bytes... PASS
scanimage: stepped read, 128 bytes... PASS
scanimage: stepped read, 256 bytes... PASS
scanimage: stepped read, 512 bytes... PASS
scanimage: stepped read, 1024 bytes... PASS
scanimage: stepped read, 2048 bytes... PASS
scanimage: stepped read, 2047 bytes... PASS
scanimage: stepped read, 1023 bytes... PASS
scanimage: stepped read, 511 bytes... PASS
scanimage: stepped read, 255 bytes... PASS
scanimage: stepped read, 127 bytes... PASS
scanimage: stepped read, 63 bytes... PASS
scanimage: stepped read, 31 bytes... PASS
scanimage: stepped read, 15 bytes... PASS
scanimage: stepped read, 7 bytes... PASS
scanimage: stepped read, 3 bytes... PASS
[root@localhost sane-1.0.1]# scanimage: stopping scanner...
scanimage: stopping scanner...
scanimage: stopping scanner...
scanimage: stopping scanner...

.. and so on: the scanner never stop.

This results and the head position problem let me think that it acts
as if the generic scsi commands were recognized by the ppSCSI module,
but not the hardware specific ones. Perhaps a problem with the onSCSI
module (but I could be wrong, as I don't know the scsi
interface/protocol at all).

That's all for now. Thank you for your help.
Bye

-- 
Regards,

Camille Diou

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