plustek: Thread: u12 - problems

hi

i have a plustek OpticPro U12,
amd athlon on gigabyte 7IX board (amd756 viper chipset)
mandrake 8.1 standard kernel (2.4.8-26mdk)

after successfully invoking scanimage a few times,
the scanner no longer answers.

this problem is non deterministic to me. anyone any ideas?
i have read somithing about usb problems with amd chipsets. because the
scanner is the only usb hardware i own, i cannot test if this is the
reason of my problmes.

thanks
    Holger


in /var/log/messages i get messages like:
----------------------
...
Dec 16 11:06:23 bird kernel: usb_control/bulk_msg: timeout 
Dec 16 11:06:40 bird kernel: usb-ohci.c: bogus NDP=64 for OHCI usb-00:07.4 
Dec 16 11:06:40 bird kernel: usb-ohci.c: rereads as NDP=0 
Dec 16 11:06:43 bird kernel: usb_control/bulk_msg: timeout 
--------------------------

the last lines i got form debugging (SANE_DEBUG_DLL, SANE_DEBUG_PLUSTEK)
--------------------------
...
[plustek] sanei_lm9831_read: succeeded
[plustek] Data is available
[plustek] sanei_lm9831_read: fd=3, reg=0, len=163328, increment=0
[plustek] sanei_lm9831_read: writing command: 01 00 ff ff
[plustek] sanei_lm9831_read: read 65535 bytes
[plustek] sanei_lm9831_read: writing command: 01 00 ff ff
[plustek] sanei_lm9831_read: read 65535 bytes
[plustek] sanei_lm9831_read: writing command: 01 00 7e 02
[plustek] sanei_lm9831_read: read 29696 bytes
[plustek] sanei_lm9831_read: short read (29696/32258)
[plustek] sanei_lm9831_read: trying again
------------------------------------------------


-- 
Holger Bischof                          | Tel.: +49-030-314-21764
TU Berlin, Sekr. FR 5-6                 | Fax.: +49-030-314-73291
Franklinstr. 28/29                      | e-mail: ####@####.####
10587 Berlin, Germany