Use some device ID in calibration file name for uniqueness
A minor issue, but I happen to have two canon lide 210, and they both create the same .cal file "~/.sane/canon-lide-210.cal" which alternatingly makes them give broken scans if the wrong calibration is used.
If that's considered too be too much of an edge case then feel free to close :)
Edited by Christoph Reiter