> Vipers can't do autodetection. You have to create different devices
> for different densitys. Minor number 8 = 120Mb, 4 = 150Mb and
> 12 = QIC-24 (60Mb). At least this is the only way it works for me,
> and since it do i haven't bothered to find out why minor 0 doesn't.
> If you have a 2525 (525Mb) it uses  ST_Q_SENSE_HELP quirq but it
> might not work.

My Viper-150 autodetects fine.  Well, almost fine; the first attempt to
read a tape fails after a boot due to an "illegal SCSI command"; I assume
that the driver is trying to use some SCSI-2 command to set the default
density -- but after that, the drive is perfectly happy to do the tedious
density check and off it goes.  I've read all three densities on the drive.