Created attachment 319160 [details]
Output of emerge --info
Since some time (I'm afraid I don't know exactly since when, but it must be 3-4 months at maximum) scanning from an ethernet-connected HP Color LaserJet CM1312nfi has ceased to work. This multifunction printing/scanning/faxing device is driven by hplip and the binary plugin, and used to work properly with all functionality expected.
Now, trying to scan with either xsane or skanlite fails, while using the respective HP-utility from hplip (hp-scan) works. The error outputted by xsane and skanlite is "Invalid argument". Downgrading to sane-backends-1.0.19-r2 and hplip-3.11.10 resulted in the error changing to "Device I/O-Error". Any other combination of a more recent hplip (3.12.x) and sane-backends yielded the forementioned "Invalid argument" error. What does work is acquiring a preview scan in skanlite as well as in xsane, but as soon as one clicks the "Scan" button, the "Invalid argument" error is thrown. It does not matter how the scan is set up, the error occurrs for gray as well as colored scans for any resolution possible.
The only error that hp-check -b gives is that xsane was missing (but it is installed and can be executed, just doesn't work properly because of the error above).
emerge --info is attached.
If you are able to scan hp-scan it seems xsane and skanlite do not get along with changes in hplip.
It is probably worth to open a bug about this upstream at https://bugs.launchpad.net/hplip anyway. Can you please do so and report the bug number here?
The bug is filed at https://bugs.launchpad.net/hplip/+bug/1029641 .
Xsane works fine here with a HP Photosmart 6510 (no plugin needed).
Can you try upgrading to the latest version of hplip-3.12.10a (do not forget to upgrade the binray plugin as well). Then restart cups, delete and re-configure all printer queues. Please report back if this fixes the problem.
Still a problem with hplip-3.13.9?