[sane-devel] sanner still jogs - more buffering ?

Pete Lancashire pete at petelancashire.com
Mon Jun 6 18:49:59 UTC 2011

Looking for suggestions on how to get my scanner to scan a full page
at full speed and
not have to 'jog' 3 or 4 times.

Scanner is a Epson GT-30000. In slow speed it works, in full speed it "jogs"

System: HP DL580G3
     4 ea dual core 3GHz Zeon cpus

     Adaptec 29320 PCI-X 133 on a bus not shared with any other PCI device
     LSI ?? 320 PCI-X 133 on a bus not shared with any other PCI Device


     8 GB  RAM DISK created from the above RAM

    Latest packages from Epkowa

    dll.conf consists of only epkowa

Scanner Epson GT-30000 Connected VIA SCSI 68 pin (wide)
Scanner ONLY RUNs at SCSI-2, 20 MB/s (40 MB/s transfer since wide I AM
ASSUMING THIS, waiting to hear back from Epson)
    NOTE: Just confirmed from Epson, their online documentation lies
in that it says SCSI-3
A full scan, 600 DPI color at full speed should take 8.058 Seconds and
create a file approx 204 MBytes
0.79 mS per line, 10,200 lines
7,020 x 10,200 or 71,604.000 pixels
24 bits per pixels

The key is 204.86 Megabytes in 8.058 Seconds which is 25.43 Megabytes
per second.

tests were done sending the output of scanimage to /dev/null.

time scanimage --color-correction='No Correction' --mode=Color
--resolution=600 --speed=yes > /dev/null

some of the things I've done and tried

installed the latest epkowa packages

changed dll.conf to just epkowa (deleted everything other then epson2
which is commented out)

increased /proc/scsi/sg/def_reserved_size to 1 Meg
changed .../allow_dio to 1 (enable)
increased SANE_SG_BUFFERSIZE to 1 Meg (and even higher)

I've also downloaded the lastest sane, built it with gcc -march / tune
= native, same resulits

Increasing the buffers to their max/1MB does help

>From the sources can I increase the buffer(s) in sane ? I have 16 GB
or RAM to play with

Can I 'sniff' the SCSI bus to see if it is sane telling the scanner to
wait or is it the scanner it self ?

Other suggestions ?

TIA ....


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