bug#38064: Simple Scan: Scanner is not detected

bug#38064: Simple Scan: Scanner is not detected

[sirgazil via Bug reports for GNU Guix]

I can't use the scanner because Simple Scan (a.k.a. Document Scanner) does not detect it.


## Steps to reproduce

1. guix install simple-scan
2. Connect the scanner.
3. Launch Simple Scan.
4. Click the Scan button in Simple Scan.


## Unexpected behavior

In step 3, Simple scan displays the following warning:

```
No scanners detected

Please check your scanner is connected and powered on
```

In step 4, you see the following message:

```
Failed to scan

No scanners available. Please connect a scanner.
```


## Expected behavior

* The scanner is detected in step 3 (no warning message is shown).
* Performing step 4 makes the scanner scan.


## System information

I'm using the Guix System and simple-scan 3.34.1:

```
$ LANG=C guix describe
Generation 5	Nov 04 2019 14:24:15	(current)
  guix bf7b08c
    repository URL: https://git.savannah.gnu.org/git/guix.git
    branch: master
    commit: bf7b08c4fe7d14c25a83bde99f19eca1119d88ff
```


## Additional information

The scanner works. I can use it from a Trisquel 8 Live USB stick, which comes with Simple Scan.

Running simple-scan from a terminal displays the following warnings:

```
$ LANG=C simple-scan

(simple-scan:3953): Gtk-WARNING **: 18:42:44.193: Failed to register client: GDBus.Error:org.gnome.SessionManager.AlreadyRegistered: Unable to register client
```

---
https://sirgazil.bitbucket.io/

bug#38064: Simple Scan: Scanner is not detected

[Jack Hill]

On Mon, 4 Nov 2019, sirgazil via Bug reports for GNU Guix wrote:

> I can't use the scanner because Simple Scan (a.k.a. Document Scanner) does not detect it.

That's unfortunate. I think the follow information might help in 
troubleshooting:

What scanner is it, and how is it connected (e.g. USB)? What does running 
`scanimage -L` from the terminal report? scanimage can be found in the 
sane-backends package (yes, it contains frontends too :)) I expect this to 
also report no scanners found just like simple-scan, but it's worth 
checking just to be sure.

I've added `(simple-service 'custom-udev-rules udev-service-type (list sane-backends))`
to my system services, which may help the scanning tools have permission
to access your scanner.

Best,
Jack

bug#38064: Simple Scan: Scanner is not detected

[sirgazil via Bug reports for GNU Guix]

Hi, Jack.


---- On Mon, 04 Nov 2019 23:16:09 -0500 Jack Hill <jackhill@jackhill.us> wrote ----

 > On Mon, 4 Nov 2019, sirgazil via Bug reports for GNU Guix wrote: 
 >  
 > > I can't use the scanner because Simple Scan (a.k.a. Document Scanner) does not detect it. 
 >  
 > That's unfortunate. I think the follow information might help in 
 > troubleshooting: 
 >  
 > What scanner is it, and how is it connected (e.g. USB)? What does running 
 > `scanimage -L` from the terminal report? scanimage can be found in the 
 > sane-backends package (yes, it contains frontends too :)) I expect this to 
 > also report no scanners found just like simple-scan, but it's worth 
 > checking just to be sure. 


It's an HP Scanjet 2200c (connects using USB). Scanimage can't find it either:

$ scan-image -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).


 > I've added `(simple-service 'custom-udev-rules udev-service-type (list sane-backends))` 
 > to my system services, which may help the scanning tools have permission 
 > to access your scanner. 

But that SOLVED the issue :) I did the following:

1. Open my system configuration file.
2. Import (gnu packages scanner) to be able to use sane-backends in step 3.
3. Add (simple-service 'custom-udev-rules udev-service-type (list sane-backends)) to the list of services.
4. Save the changes.
5. Reconfigure the system with

      $ sudo guix system reconfigure ~/path/to/my-config.scm

6. Reboot.

After this, when I start the Document Scanner application it reports:

```
Ready to scan
HP Scanjet 2200c
```

And I can scan successfully. 

Thanks, Jack.


P. S.: Now I wonder if https://debbugs.gnu.org/cgi/bugreport.cgi?bug=35584  can be solved in a similar way...


---
https://sirgazil.bitbucket.io/

bug#38064: Simple Scan: Scanner is not detected

[sirgazil via Bug reports for GNU Guix]

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I'm closing this issue as it was not really a bug in Simple Scan, but a missing service in the system configuration provided by the Guix System installer.

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