[sane-devel] lamp going off on scanning pass - scans all black

[John Youells]

I have an old hpIIcx  running on  gentoo linux with a 2.6.5  kernel .  
In order to keep either a Symbios 825a or  BT-930 from timing out and 
reseting I have changed line 283 in sanei_scsi to :
static int sane_scsicmd_timeout = 7200;  and then with these options set 
in hp.conf:
scsi HP
/dev/sg0
option dumb-read (BT530)
or
option scsi-connect (Symbios 825)

the IIcx makes all the right noises and and scanner moves but the lamp 
goes off just before the final scan pass and my images are all black.
I know that the BT-930 has been a problem in the past but I have also 
tested with aha3940, aha2940u, and sym53c825a with either the  same or 
even less results. Until about 16 dec 03 the scanner was working fine in 
both gentoo an win2k with the aha3940 and a few other scsi devices 
(testing with only the scanner now...). I believe I was running 
sane-backends-1.0.12-r2 in dec. In testing I have gone back thru all the 
versions from 1.0.14-pre1 to 1.0.9 (modifying the sane_scsicmd_timeout = 
7200 each time) and looking at debug logs from sane, but my scan lamp 
turns off just before the scan pass an results in an all black image in 
both scanimage, xsane, and kooka (vuescan segfaults). 

I have also tested with gentoo-sources 2.4.26  with the same results 
with all scsi adapters. 
I have been looking thru the source and looking at debug logs but the 
code is over my head so far, I still can't tell if the IIcx has broken 
or if there is a bug. Can anyone give any debugging suggestions, or 
throw any light on this problem.

John Youells