[sane-devel] avision backend support of HP 8250

[Anastas Giokov]

I have recently bought an HP 8250 scanner and tried to use it with
sane. Although the scanner support is marked as "good" it hangs when
trying to communicate with it.

scanimage -L recognizes device as 'avision:libusb:005:003' as a 'HP
ScanJet 8200 flatbed scanner'

scanimage -T hangs after turning scanner lamp on and off several
times. Debuging showed that hangup occurs during calibration. When
turning calibration off, scanimage -T managed to start the test scan,
hanging this time during the scanning.

Debug output shows:
...
[avision] dev->scsi_buffer_size / 2: 524288                - ? why scsi?
[avision] bytes_per_line: 7608, pixels_per_line: 2536
[avision] lines_per_stripe: 16, lines_per_output: 16
[avision] max_bytes_per_read: 60864, stripe_size: 121728, out_size: 121728
[avision] reader_process: total_size: 26863848
[avision] reader_process: processed_bytes: 0, total_size: 26863848
[avision] reader_process: this_read: 30432
[avision] read_data: 30432
                         /--- repeats from here
[avision] try to write cmd, count: 10.
[avision] wrote 10 bytes
[avision] try to read 30432 bytes
[avision] read 0 bytes
[avision] avision_usb_status: timeout 5000
[avision] ==> (bulk read) going down ...
[avision] <== (bulk read) got: 0, status: 2
[avision] ==> (bulk read) going down ...
[avision] <== (bulk read) got: 0, status: 2
[avision] ==> (bulk read) going down ...
[avision] <== (bulk read) got: 0, status: 2
[avision] ==> (bulk read) going down ...
[avision] <== (bulk read) got: 0, status: 2
[avision] ==> (bulk read) going down ...
[avision] <== (bulk read) got: 0, status: 2
[avision] ==> (bulk read) going down ...
[avision] <== (bulk read) got: 0, status: 2
                                    --/ to here several times.
...

How can I look at the actual communication between the backend and the
scanner? I'd like to debug further if anybody has an idea where to go
next.

Best regards,
Anastas