Comment 1 for bug 313504

This problem is occuring with any multi function usb device that supports [scanning and [printing or cardreader] ].

The problem is that the usblp and/or usb_storage kernel modules claim the usb device (at least de sub-intrefaces for printing/usb storage).

The sane usb backends seem to try to claim the whole usb device, but this is rejected as the "other" interfaces are already claimed.
There seems to be a workaround in sane 1.0.17-1 that ignored the EBUSY state of the usb device, which worked for most devices.
Somehow this seems to be broken in the newer versions.

One solution to use the scanner is to do "modprobe -r usblp" and "modprobe -r usb_storage" before scanning and re-insert the modules using "modprobe usblp; modprobe usb_storage" afterwards but this seems no practical way to work...

You may try to downgrade the sane packages to 1.0.17-1 (some websites show that 1.0.18 also works) and try with these.

I have the same issue with a Debian system and a Brother MFC-215C, having scanner, card reader, printer and fax function.

I will try this downgrade fix next week and report back.