On 28.1.2016, at 9.36, Seymour, Shane M [off-list ref] wrote:

Hi Kai,

With the changes the I get a failure partitioning a HP DAT72 drive (DDS-5):

# ./mt -f /dev/st1 stsetoption debug
# ./mt -f /dev/st1 stsetoption can-partitions
# ./mt -f /dev/st1 mkpartition 1000
/dev/st1: Input/output error

...

[ 3976.389605] st 6:0:3:0: [st1] Partition page length is 10 bytes.
[ 3976.389610] st 6:0:3:0: [st1] PP: max 1, add 0, xdp 0, psum 02, pofmetc 0, rec 03, units 00, sizes: 0 65535
[ 3976.389614] st 6:0:3:0: [st1] MP: 11 08 01 00 10 03 00 00 00 00 ff ff
[ 3976.389618] st 6:0:3:0: [st1] psd_cnt 2, max.parts 1, nbr_parts 0

                                                     ^^^^^^^^^
The problem is here

...

Using a slightly older kernel to partition the DAT72 drive works (same 3 commands as above):

...

[  351.584906] st 6:0:3:0: [st1] Partition page length is 10 bytes.
[  351.584908] st 6:0:3:0: [st1] psd_cnt 1, max.parts 1, nbr_parts 0

The old driver computes the psd_cnt from the returned page length. The same applies
to the patched driver if the SCSI level of the device < SCSI_3. This works correctly with
my drive that reports SCSI_2. So, the question is: what SCSI level does your device
report?

Kai