Hello,
The code for this umass attachment (dev/usb/umass_isdata.c) doesn't use the
atabus, and sidesteps the normal atabus processing. Today I discovered that
after the NCQ branch was merged, some kernels which included
dev/usb/usbdevices.config but no atabus failed to compile due to missing
symbols, and added some bandaid for that.
As part of NCQ branch, I made efford for the umass_isdata.c code to
continue compile, but had no way to test if it actually still works. In
fact, I have no idea if the code worked before I started on NCQ. Nobody
responsed also when I asked for testers for this particular device in half
a year.
As the hardware is relatively rare, it's actually quite difficult to keep
maintaining this while working on more advanced ATA features. I think it
would be fair to simply drop it from tree. If some brave soul wants to
revive it, it would be available in the history.