[sane-devel] Looking to add support for Avision AV50F plus scanner

[Ove Laurum]

Thanks Ralph, I am not familiar with udev, but I added my scanner to the
bottom of the file /lib/udev/hwdb.d/20-sane.hwdb on the VM I have the
Scanner connected to as you suggested
I  did: $ *udevadm control --reload-rules*
No luck
I rebooted the VM but I still can not see the scanner with scanimage -L

Is the scanner supposed to show up using scanimage -L?

I also tried the GUI xsane, but it also can not see the scanner.


Last 7 lines of 20-sane.hwdb:
# Dell Dell 1235cn
usb:v413Cp5310*
 libsane_matched=yes

# OVE
usb:v0638p2b6a*
 libsane_matched=yes

output from lsusb & sane-find-scanner & scanimage -L
root# lsusb
Bus 001 Device 003: ID 0638:2b6a Avision, Inc. AV50F Plus

root# sane-find-scanner

  # sane-find-scanner will now attempt to detect your scanner. If the
  # result is different from what you expected, first make sure your
  # scanner is powered up and properly connected to your computer.

  # No SCSI scanners found. If you expected something different, make sure
that
  # you have loaded a kernel SCSI driver for your SCSI adapter.

found possible USB scanner (vendor=0x0638 [AVISION], product=0x2b6a [AV50F
Plus]) at libusb:001:003
  # Your USB scanner was (probably) detected. It may or may not be
supported by
  # SANE. Try scanimage -L and read the backend's manpage.

  # Not checking for parallel port scanners.

  # Most Scanners connected to the parallel port or other proprietary ports
  # can't be detected by this program.
root# scanimage -L

No scanners were identified. If you were expecting something different,
check that the scanner is plugged in, turned on and detected by the
sane-find-scanner tool (if appropriate). Please read the documentation
which came with this software (README, FAQ, manpages).


Regards Ove.

On Wed, 4 Sept 2024 at 19:20, Ralph Little <skelband at gmail.com> wrote:

> Hi,
>
> On Wed, Sep 4, 2024 at 10:11 AM Ove Laurum <laurum.tech at gmail.com> wrote:
>
>> Thanks Ralph,
>>
>> I found the code on GitLab. Very useful.
>>
>> I also managed to add my scanner to the config file
>> /etc/sane.d/avision.conf
>> usb 0x0638 0x2b6a
>>
>
> Great.
>
>
>>
>> I didn't get much of a trace out until I ran it as root, see abbreviated
>> output below
>> SANE_DEBUG_AVISION=100 scanimage -L
>> (I don't think I can use the -d option unless the device is listed with
>> "scanimage -L")
>>
>> When I do:
>> SANE_DEBUG_AVISION=50 sane-find-scanner
>> I get no trace, is that because the backend is not involved at this stage?
>>
>
> Yeah, that won't work. sane-find-scanner is not using the SANE API at all.
> It merely looks for devices that might be scanners.
> You should use scanimage or another SANE frontend instead. This *should*
> work once the avision backend knows about your scanner.
> I *think* that you can use -d avision to pick the first avision device.
>
>
>>
>> In the trace that I did get, it looks like the backend is opening the
>> correct device "libusb:001:003" and tries a first command which is
>> "Inquiry".
>> It builds the query and tries to write it but fails with error code 9.
>>
>> I am running the command as root (not as sudo) so it should not be a
>> permissions issue unless the backend is run by a different user.
>> If I run as an unprivileged user then I do not even get this far. In that
>> case it tries to access the scanner but fails and is not even getting to
>> the stage of Attaching to the scanner.
>> Also worth noting is that my Canon LiDE220 works fine with sane, which is
>> another indicator that it is unlikely a permissions issue.
>>
>
> Permissions are generally handled by udev which has rules based on USB ids
> to give permissions to non-root users.
> Just adding the USB ids to the backend will not be sufficient. You *could*
> add the USB ids to a udev file such as /lib/udev/hwdb.d/20-sane.hwdb
> followed by running something like
>
> *udevadm control --reload-rules*
>
> ...as root. This should allow you to connect to the device as a regular
> scanning user.
>
>
>>
>> So based on the trace and on the source code it looks like it is:
>>
>>    - Attaching to the scanner.
>>    - SANE_Status = SANE_STATUS_GOOD in reply to sanei_usb_open
>>    - starts building an inquiry
>>    - tries to send the inquiry
>>    - fails to do sanei_usb_write_bulk
>>    - sanei_usb.c responds with error
>>
>> How can I see log entries from sanei_usb.c code?
>>
>>
> I believe SANE_DEBUG_SANEI_USB=5 will give you some info about sanei USB
> operations. Greater value gives you more info.
>
> Cheers,
> Ralph
>
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