[sane-devel] multiple, identical scanners?

Johannes Meixner jsmeix at suse.de
Wed Nov 11 08:31:44 UTC 2015


On Nov 10 14:09 Jeremy Chacon wrote (excerpt):
> ... sometimes gives an I/O Error ...

In general "sometimes I/O Error" indicates that the root
cause is somehow hardware related where "hardware" means
the actual computer hardware plus the computer's built-in
firmware (i.e. BIOS or UEFI) and "hardware related" means
computer hardware plus firmware plus Linux kernel driver
plus low-level hardware related software (e.g. libusb).
You may have a look at "a stack consisting of various
layers must be functional in its entirety" in

You did not tell how your scanners are connected to your

If your scanners are connected via USB:

There are currently issues with USB ports where the kernel
module "xhci" is used as kernel driver.
When "lsusb -t" shows "Driver=xhci_hcd" for the USB bus
and port where the USB scanner is connected (see "lsusb" where
the scanner is connected), then there could be issues depending
on the computer hardware and firmware.
In this case see
in particular see
that reads (excerpt):
My machine has 4 USB ports, two labeled with
the "super speed" USB logo (a.k.a. USB 3) and
two labeled with the normal USB logo (a.k.a. USB 2)
but for all 4 ports xhci is used and it fails on all 4 ports.
and see

When your scanner is not connected at a USB port where the
kernel module xhci_hcd is used as kernel driver (e.g. when
your scanner is connected at a USB port where the kernel
module uhci_hcd or ehci_hcd is used as kernel driver),
then have a look at "Trouble-Shooting (Debugging)" in

For example in your case to get USB debugging information
you could use comands (as root) like
scanimage -L

Kind Regards
Johannes Meixner
SUSE LINUX GmbH - GF: Felix Imendoerffer, Jane Smithard,
Graham Norton - HRB 21284 (AG Nuernberg)

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