Firewire devices with multiple LUNs

[Andy S. <and...@gm...>]

Hello Firewire fans,

I am trying to use a Firewire device which is a magnetic tape autoloader. I
have used these many times successfully with LVD-SCSI, but not previously
with Firewire.

With LVD-SCSI, you can set two distinct SCSI IDs for the hardware (one for
the tape drive, and one for the autoloader robot). Then, I get two sg
devices mapped (e.g. /dev/sg3 for the tape drive, and /dev/sg4 for the
robot). This all gets detected automatically at boot time.

With Firewire, there is only one SCSI ID detected. At boot time, I both
devices in the dmesg log (the tape drive with LUN=0000, and the robot with
LUN=0001). But I only get a single sg device for the tape drive, and not
the robot.

Other times at random, a boot up will only detect a single LUN=0000 for the
robot, and a corresponding sg device for the robot. And the tape drive is
not detected at all!

Any suggestions on how to make the Firewire device detection a bit more
consistent and repeatable? Is there any way to control it by writing to
/proc file system?

I am using Debian 8.10, with Linux kernel 3.16.0 and firewire-sbp2. I have
also tried on Debian 9 with similar results.

Regards,

--Andy Stevens
Port Chester, NY