[sane-devel] libusb vs linux kernel scanner driver

m. allan noah anoah@pfeiffer.edu
Fri, 11 Jul 2003 09:22:59 -0400 (EDT)

i am running usb fujitsu scanner on linux 2.4.21. the fujitsu backend uses 
sanei_usb, so both the kernel scanner driver, and libusb work. however, libusb 
causes a long pause, and a couple of timeouts happen, before the scanner starts. 
after that, the multi-page (adf) scans proceed normally, with no other errors.

so i did two scans with SADE_DEBUG_SANEI_USB=255, one with kernel scanner 
driver, one with libusb, and i compaired the parts prior to the pause using 
libusb. the usb packets, and the order they are sent in are the same.

so, it would seem to be lower level than the backend. anyone know how can i get 
more debugging info from the kernel scanner driver and libusb, so that i can see 
exactly what packets are going out to the device, and what sort of time 
signature they have?


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