Hi Kai,

$ pwd
/sys/class/scsi_tape/st1/device
$ cat scsi_level
4

Thanks
Shane

-----Original Message-----
From: "Kai Mäkisara (Kolumbus)" [mailto:kai.makisara@kolumbus.fi]
Sent: Friday, January 29, 2016 4:04 AM
To: Seymour, Shane M
Cc: Laurence Oberman; Emmanuel Florac; Laurence Oberman; linux-
scsi@vger.kernel.org
Subject: Re: What partition should the MTMKPART argument specify? Was:
Re: st driver doesn't seem to grok LTO partitioning

quoted

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

wrote:

quoted

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

...

quoted

[ 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

...

quoted

Using a slightly older kernel to partition the DAT72 drive works (same 3

commands as above):
...

quoted

[  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

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