Very slow colour scanning with Trust Imagery 1200SP (= Mustek MSF-06000SP)

Robert Brink (linux4me@dds.nl)
Thu, 31 Dec 1998 13:10:55 +0100

After many attempts I finally got my Trust Imagery 1200SP scanner to work with
SANE and Linux. Because the original SCSI card shipped with the scanner
(NCR53c400a) didn't work with Linux (kernel lockups after installing the
driver), I used an Adaptec AVA1505 (ISA SCSI host adapter) instead. Now the
Windows TWAIN driver doesn't recognize the scanner anymore, but GIMP is a good
alternative for commercial Windows programs, so that is not a big deal.

Anyway, I noticed the following differences between my Linux configuration
running SANE (with xscanimage, GIMP and sane-mustek) and Windows running TWAIN:

1. When scanning a colour image, the scanning head moves forward and back all
the time, although I had not enabled "Force backtracking". All together
scanning a simple phothograph with 200 dpi takes over 5 minutes, while with
TWAIN this was a matter of seconds. I enlarged the buffer size in sg.h to
128kb and recompiled the kernel, but that didn't seem to have effect.

2. When scanning a preview, grayscale or lineart image, speed is the same as
with TWAIN, although colour previewing has a slight backtracking. So I disabled
colour previewing :-)

3. CPU load is almost 100%, during scan you can't even move the mouse
pointer!!! This is probably caused by a bad interaction between the SCSI
adapter and the scanner, the latter not supporting SCSI disconnect. I could
replace the ISA card with a PCI card supporting bus-mastering DMA, but then
again, I have to spend another $50 :-(

4. Gamma correction doesn't work fine, it causes the picture to look
over-exposed very quickly (with white turning into blue). There may be a
possibillity I have overlooked, as I don't know whether the scanner has
built-in NVRAM which keeps downloadable software settings in memory. That would
definitely impair scanning quality.

This is the hardware information my Linux (2.0.36 kernel) system gave me:

bash$ cat /proc/scsi/scsi
<other SCSI stuff deleted for clarity :-)>
Host: scsi1 Channel: 00 Id: 00 Lun: 00
Vendor: MUSTEK Model: MSF-06000SP Rev: 2.10
Type: Scanner ANSI SCSI revision: 01

bash$ cat /proc/scsi/aha152x/1
Adaptec 152x SCSI driver; $Revision: 1.18 $
ioports 0x0340 to 0x035f
interrupt 0x09
disconnection/reconnection disabled
parity checking enabled
synchronous transfers disabled
0 commands currently queued
enabled debugging options: (abort) (reset)

Anyone knows what I might have configured wrong? Or is it just a buggy firmware
revision?

TIA and a happy new year :-)

Robert Brink
linux4me@dds.nl

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