There seems to be some change 2.2->2.4 with the generic SCSI layer that's
upset xsane. Normal scanning seems fine, but 'acquire preview' fails with
Seems to be a kernel thing. Investigating, with help from Douglas Gilbert.
Okay, this seems to be a sane problem, fixed in 1.0.4. Need to upgrade.
In fact it turns out not even to be fixed in sane 1.0.4. I've applied the fix
(increase the timeout for sg v3) in sane-1.0.3-9.