[sane-devel] libusb - problems with open/close of device in backend?
Mon, 23 May 2005 11:12:58 -0500
Still working on the microtek2 backend stuff for libusb...
It seems that the odd issues I'm encountering will go away if I don't
ever close the USB device. If I leave it open for the duration of the
backend lifetime, scanimage -L will properly identify it. If I open
and close it for each operation, I get timeouts trying to read
responses, and if I increase the response size the scanner will send
back a larger packet which seems to show that I miss the first block
of data (32-bytes for this scanner).
Is this a problem anywhere else with the libusb stuff?
Is there harm in leaving the scanner open until sane_exit ?
At least for now doing this allows scanimage -L to find the scanner.
That is good. However, another glitch is cropping up when I try to
send the system_status block back to the scanner... The USB log shows
the transmission is without error, but after that point I get no more
response from the scanner to the remaining commands. The odd thing
is, I've not changed anything about the logic of what is being sent
to the scanner, just sending it via libusb instead of writing to the
fd of the linux kernel scanner driver. Oh well. :-)