IEEE 1394 for Linux

As has been reported a few times on the linux1394-devel
mailing
list, hotplugging firewire drives only sortof works. A
recent
posting to the list rehashing the problems


http://sourceforge.net/mailarchive/forum.php?thread_id=1151203&forum_id
=5389

reminded me of my old partial fix for this problem that was
sitting unfinished. So last night I polished it up,
fixed the
bugs, and it is now working perfectly for me.

Without this patch, hotplugging firewire drives will
register the
drives with the 1394 layers, but will not register them
with the
SCSI subsystem. Unplugging firewire drives leaves the (now
absent) drives still registered with the SCSI
subsystem. As you
can imagine, the current situation sucks, and makes
hotplugging
firewire drives mostly useless. To make things behave
correctly,
one needs to manually add/remove SBP-2 devices using a
shell script
(http://www.garloff.de/kurt/linux/rescan-scsi-bus.sh) that
pokes at /proc/scsi/scsi by scanning though all your
SCSI hosts
and then does things like
echo "scsi remove-single-device 0 0 0 0" >
/proc/scsi/scsi
for each and every SCSI device on your system. I don't
consider
such things safe or desirable at all.

It seemed to me that since the kernel had all the
information to
do the Right Thing(tm), it made sense to connect the
remove-single-device and add-single-device functionality of
/proc/scsi/scsi together with the sbp2 driver so the Right
Thing(tm) could happen automagically.

With my patch applied, one can now plug in firewire
drives and
they will all be automagically registered with the SCSI
subsystem. When one unplugs SBP-2 devices, they will be
automagically unregistered from the SCSI subsystem.

When I posted my earlier effort to the linux1394-devel
list:

http://sourceforge.net/mailarchive/forum.php?thread_id=949390&forum_id=
5389
it was decided that the change to the SCSI subsystem
needed to
expose scsi_add_single_device() and
scsi_remove_single_device()
was not desirable. I'll leave the decision on that to
others.

For the moment, this patch is works nicely for me and
makes using
firewire drives a much nicer experience.

Have fun,

-Erik

--
Erik B. Andersen
http://codepoet-consulting.com/
--This message was written using 73% post-consumer
electrons--