[sane-devel] Epson Perfection1640 & epson2 backend: hangs when trying to scan large area

[ael]

On Sun, Nov 07, 2021 at 08:16:42PM +0100, Wolfram Sang wrote:
> Please check if that works on your system as well.

I mentioned earlier in this thread that I had seen problems when
trying to scan large areas at high resolutions.

I have now confirmed this both with xsane and scanimage, so I suppose
that this is a problem with the epson2 backend.

An example with scanimage is

$ SANE_DEBUG_EPSON2=20 scanimage -d epson2:libusb:003:007 --format=png --mode Color --depth 14 --wait-for-button  -l 0.425 -t 10.073 -x 90 -y 76 --resolution 3200  -d epson2:libusb:002:008  --source 'Transparency Unit' --film-type 'Positive Film' 2> ~/linux/sane_bug/scanimage_overflo.txt > /tmp/try.png

The resolution of 3200 is the largest that the 1640SU supports.

$ ls -l /tmp/try.png
13651522 Nov 18 18:11 /tmp/try.png
about 14M, far too small.

/tmp/try.png just shows a few of the topmost scan lines: it is obviously
very partial.

The gzipped scanimage_overflo.txt.gz is attached.
I note it contains many lines like

moving data 0x5594ee475870 0x5594ee476220, 32768 (0 lines)

but I have barely even skimmed it.

ael