[sane-devel] Xsane locks system w/UMAX Astra 1200S

[abel deuring]

Dave,

> A few updates.
> 
> 1)  I have confirmed that the CD Writer still functions fine.
> 
> 2)  I forced the SCSI card to use IRQ 4 (serial ports are disabled).  No
> change.  I pulled some extra, unused cards out of the system and also
> moved the SCSI card to a different slot.  No change.
> 
> I'm going to try XSane .92 now.

As Oliver already wrote, updating XSane will probably not change very 
much regarding the crash. You could try to use another version of 
sane-backends, but I have doubts that this will help.

Sane frontends like XSane or scanimage are just "ordinary" user space 
programs, and the scanner specific backends are ordinary libraries 
linked to the frontends. While a frontend or a backend may contain bugs 
cuasing segfault or garbled images, it is highly unlikely that a user 
program itself can freeze a Linux box as you are experiencing. This is 
the reason that I suspect either a hardware failure -- or you hit 
perhaps a kernel bug.

One noticeable difference between most programs accessing CD 
drives/writers and Sane backend for SCSI scanners is that Sane uses 
comparatively large data sizes in its SCSI commands (typically 128 kB 
for READ commands), while CD writing software uses probably data block 
sizes < 32 kB.

It could be that these larger data block sizes are somehow related with 
your bug. (though they are not the cause, I think - Sane uses these 
block sizes since several years without any problem)

You could try to reduce the block size by setting "option 
scsi-buffer-size-min" and "option scsi-buffer-size-max" to values like 
16384 or 32768.

Abel