[sane-devel] canoscan 300 scsi scanner not detected

[Johannes Meixner]

Hello,

have in mind that on nowadays systems the generic SCSI device node
files /dev/sg* do no longer belong only to real SCSI devices
but also to whatever other kind of devices, e.g. on my system
with a plugged in "Spaceloop XL 4GB" USB stick
-------------------------------------------------------------------------
nelson:~ # lsscsi --generic
[1:0:0:0]    disk    ATA      ST3120022A       3.04  /dev/sda   /dev/sg0
[2:0:0:0]    cd/dvd  PIONEER  DVD-RW  DVR-106D 1.10  /dev/sr0   /dev/sg1
[2:0:1:0]    cd/dvd  PIONEER  DVD-ROM DVD-121R 1.00  /dev/sr1   /dev/sg2
[4:0:0:0]    disk    Sony     UMH-U HS-MS      2.12  /dev/sdb   /dev/sg3
[4:0:0:1]    disk    Sony     UMH-U HS-CF      2.12  /dev/sdc   /dev/sg4
[4:0:0:2]    disk    Sony     UMH-U HS-SM      2.12  /dev/sdd   /dev/sg5
[5:0:0:0]    disk             Spaceloop XL 4GB 8.07  /dev/sde   /dev/sg6
-------------------------------------------------------------------------
so that the number of the generic SCSI device node files /dev/sg*
may change depending on which device is plugged in first
and/or depending on which device is recognized first by the kernel.

Therefore it does no longer work reliable to have a generic SCSI
device node file hardcoded in a /etc/sane.d/<backend_name>.conf
file.

Instead the backends should do scanner autodetection for USB and SCSI
and their /etc/sane.d/<backend_name>.conf files should have
appropriate defaults.

In particular for the "canon" backend we (i.e. Novell/openSUSE)
apply this patch:
--------------------------------------------------------------------
--- backend/canon.conf.in.save  2006-07-21 09:43:08.000000000 +0200
+++ backend/canon.conf.in       2006-07-21 09:57:03.000000000 +0200
@@ -1,3 +1,12 @@
-#canon.conf
-/dev/scanner
+# canon.conf
+#
+# Activate exactly one of the following choices:
+#
+# Probe on all /dev/sg* devices:
+scsi
+#
+# Probe for "CANON" on all /dev/sg* devices:
+#scsi CANON
+#
+# Probe only on one fixed device:
  #/dev/sg0
--------------------------------------------------------------------

For more information regarding the "canon" backend have a look at
https://bugzilla.novell.com/show_bug.cgi?id=177492
in particular
https://bugzilla.novell.com/show_bug.cgi?id=177492#c11

Also see the
"device file for "canon" backend in sane-backends 1.0.17"
mail on this list in May 2006.

According to "man sane-scsi" it seems the SCSI autodetection
is not possible for all operating systems?

Otherwise it should be possible to have an upstream default
/etc/sane.d/canon.conf like
-------------------------------------------------------------------
# canon.conf
#
# Activate exactly one of the following choices:
#
# Probe on all /dev/sg* devices:
scsi
#
# Probe for "CANON" on all /dev/sg* devices:
#scsi CANON
#
# Probe only on one fixed device:
#/dev/sg0
-------------------------------------------------------------------

Or is there another reason why SCSI autodetection should
not be done by default?


On Oct 28 07:11 m. allan noah wrote (shortened):
> edit /etc/sane.d/canon.conf
>
> put the scanner device file name there.
>
> allan
>
> On Thu, Oct 28, 2010 at 6:37 AM, Denis Prost <denis.prost at wanadoo.fr> wrote:
>>  Hi everyone,
>>
>> I've got a problem with my canoscan 300 scsi scanner.
>> though it appears in sane-find-scanner output :
>> --------------
>> ...
>> found SCSI scanner "CANON IX-03035B 1.01" at /dev/sg3
>>  # Your SCSI scanner was detected. It may or may not be supported by SANE.
>> Try
>>  # scanimage -L and read the backend's manpage.
>> ....
>> ------------
>> whatever GUI I use (xsane, kooka, simple-scan...), these softwares don't
>> detect it, the only scanner they detect is my webcam.
>> To solve the problem, I have to do by hand "ln -s /dev/scanner /dev/sg3"
>> each time I plug my scanner in.
>> But that does not seem to be a very clean solution. Is that normal ?

Kind Regards
Johannes Meixner
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