[sane-devel] Problems with testbackend and non-blocking IO

[mh]

Hi (especially Henning),
while playing with the test-backend I noticed a strange behaviour with the 
non-blocking IO option enabled. E.g. a preview scan in xsane, gray/8bit, 
testimage option enabled *sometimes* causes xsane to hang.
QuiteInsane ("the not yet released version") doesn't hang, but sometimes 
returns an IO error. 
A preview scan (quiteinsane) in color mode/1bit, testimage option enabled 
reveals another odd behaviour: the preview scan looks different with every 
scan, i.e. sometimes the upper left corner isn't black. I don't change any 
options; the debug output of the backend is exactly the same for all preview 
scans. If I disable non-blocking IO, it works just fine.
Did anyone else notice this?
To Henning: If you like to test this, I can send you a patch for 
quiteinsane-0.4.1. (~ 150 kB).

bb
Michael