[sane-devel] Epson ES-50 errors and misbehavior

[Sparr Risher]

I am using sane 1.4.0 with my Epson ES-50 (aka J421B). I am experiencing a
few problems, potentially some or all of which have the same root cause.
I'm moderately proficient with troubleshooting and coding in C, but I know
nothing about scanner protocols or how the sane codebase is organized. I am
hoping someone here might be able to give me some pointers on where I
should look first in digging into one or more causes for these issues:

In some frontends, including Gnome simple-scan, when I attempt to scan an
additional page into a batch, I am told there is no document in the feeder
on alternating attempts. First page scans fine (almost?) every time. First
attempt to add a page fails. In scanimage, as soon as that attempt fails,
the batch ends. In Gnome simple-scan, I can click the button to add a page
to the batch again and the second attempt will succeed, then I click again
and the third attempt fails, and again and the fourth attempt succeeds, etc.

Every frontend I've tried produces 8.5x14" images when I scan 8.5x11"
pages. The unscanned area is solid white.

Every page I scan with scanimage produces additional output to stderr
"Corrupt JPEG data: found marker 0xd9 instead of RST3"

When I run scanimage in -T -v mode it also ends its output with "FAIL
Error: End of file reached"

Here is one session showing all of the problems except the last one, where
I attempt to scan two 8.5x11 pages and get one 8.5x14 output image then a
failure:

% scanimage -L
device `epsonds:libusb:003:004' is a Epson ES-50 ESC/I-2

% scanimage -v -b --batch-prompt --format=pngScanning infinity pages,
incrementing by 1, numbering from 1
Place document no. 1 on the scanner.
Press <RETURN> to continue.
Press Ctrl + D (EOF) to terminate.

Scanning page 1
Corrupt JPEG data: found marker 0xd9 instead of RST4
scanimage: scanning image of size 1696x2795 pixels at 24 bits/pixel
scanimage: acquiring RGB frame
scanimage: min/max graylevel value = 0/255
scanimage: read 14220960 bytes in total
Scanned page 1. (scanner status = 5)
Place document no. 2 on the scanner.
Press <RETURN> to continue.
Press Ctrl + D (EOF) to terminate.

Scanning page 2
scanimage: sane_start: Document feeder out of documents
Batch terminated, 1 page scanned
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