Hi, I answer both allan and abel in this mail.
> we can also add a function like sane_get_device_information to the > Sane API that would return data like USB bus and devices numbers [?] > A HAL callout can then call sane_get_devices, call > sane_get_device_information for each Sane device and can this way > decide, if a Sane device "matches" the "current" HAL device. So basically, we have have two solutions : 1. a HAL callout + sane_get_device_informations()? 2. a SANE meta backend 3. extends the meaning of sane_open() I actually prefer the first since it imply less modification in SANE. Something good would be to avoid reloading all backends since HAL know which backends support the device. Something like sane_backend_get_devices would be very cool. Which solution is the right ? Other solution are welcome ;) Please comment. Many thanks Abel for commenting. Regards, ?tienne.