[sane-devel] HP Scanjet 3P io errors
Sun, 22 Jun 2003 22:25:13 +0200
> I found nothing related in the archives:
It' s a bit difficult to find ;) I needed a few minutes to search
through my private mail archive to find the the answer.
> Using sane front & back ends v1.0.7
> Device is Scanjet 3P and ADF, model 2570A, firmware 3430.
> Connected to Buslogic BT946C.
> sane does not seem to like my scanner. It returns io device errors.
> Works fine with epson scanner.
In short: The combination Buslogic driver/Linux kernel 2.4/HP scanner
does not work well.
The longer explanation: For certain commands, the HP backend cannot
predict the exact size of a data block returned for a certain SCSI
command. If the scanner return less or more data than "declared" by the
backend, the Buslogic driver raises an error and does not return any data.
This data underrun/overrun is not an issue for most other scanners -- in
general, the Sane backends can precisely predict the length of tha sent
to/received from the scanner.
The short conclusion: Use another SCSI adapter for the HP scanner. The
longer conclusion: The Buslogic driver would need a new maintainer, who
can continue the work of the late Leonard Zubkoff.