Thanks for the replies so far, which I've followed up with ideas of my own.
(1) In /etc/sane.d/dll.conf (at the end) it lists # Add support for the Epson-specific backend. Needs media-gfx/iscan installed epkowa I've installed 'iscan', but it makes no difference. (2) The 2 pkgs which mb relevant & which have been updated > 180626 are the kernel & 'gtk+:2' : syslog reports use of 'ehci-pci', but that is enabled in my kernel 4.14.52 ; might 'gtk' be the problem ? (3) I can scan without problems using Mint Xfce (on another partition), so it's not a hardware problem. (4) 'lsusb' lists "Bus 001 Device 004: ID 0418: 013b Seiko Epson Corp". (5) the 'epkowa' driver is the latest version : a download from 'support.epson.net/linux/en/iscan.php?model=perfection-v550&version=1.0.1' gets the same compressed files as are already installed (same sizes). (6) the output from 'strace' is at http://chass.utoronto.ca/~purslow/test/xsane-trace.d1 . (7) When the scanner is switched on (already connected), syslog says : usb1-3: new high-speed USB device number 3 using ehci-pci New USB device found, idVendor 04b8, idProduct 013b strings: MFr=1, Product=2, SerNo=0 Product: EPSON Scanner; Manufacturer: EPSON (8) Users at Ubuntu have been having problems starting Autumn 2017 : https://bugs.launchpad.net/ubuntu/+source/sane-backends/+bug1728012 : see esp # 20 & # 144 . (9) Vuescan is a possible alternative : does anyone have experience ? Further thoughts from anyone are very welcome. -- ========================,,============================================ SUPPORT ___________//___, Philip Webb ELECTRIC /] [] [] [] [] []| Cities Centre, University of Toronto TRANSIT `-O----------O---' purslowatchassdotutorontodotca
