Date: Sun, 14 Jul 1996 12:40:37 +0200 (MET DST) From: J Wunsch <j@uriah.heep.sax.de> To: freebsd-scsi@freebsd.org Cc: jbh@labyrinth.net.au (John Hartley) Subject: Re: tandberg scsi tape + FreeBSD 2.1/2.0.5 Message-ID: <199607141040.MAA00518@uriah.heep.sax.de> In-Reply-To: <199607140517.PAA17083@minotaur.labyrinth.net.au> from John Hartley at "Jul 14, 96 03:17:33 pm"
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As John Hartley wrote:
> >+ {"Tandberg tdc4100", "TANDBERG", " TDC 4100", "????",
> >+ ST_Q_NEEDS_PAGE_0|ST_Q_SNS_HLP,
^^^^^^^^^^^^^^^^^^
Take this out again. :) It hurts when i do so... We are now
violating the specs by setting the PS bit in a MODE SELECT command:
``When using the MODE SENSE command, a parameters savable (PS) bit of one
indicates that the mode page can be saved by the target in a non-volatile,
vendor-specific location. A PS bit of zero indicates that the supported
parameters cannot be saved. When using the MODE SELECT command, the PS bit is
reserved.''
> Jul 14 14:51:19 qwiff /kernel: st0(ahc0:2:0): command: 1a,0,0,0,18,0-[24 bytes]
> Jul 14 14:51:19 qwiff /kernel: ------------------------------
> Jul 14 14:51:19 qwiff /kernel: 000: 2f 25 10 08 15 00 00 00 00 00 02 00 90
^^
That's better than what it used to be before! It now properly reports
density 0x15 on the first attempt.
> Jul 14 14:51:20 qwiff /kernel: st0(ahc0:2:0): command: 15,0,0,0,18,0-[24 bytes]
> Jul 14 14:51:20 qwiff /kernel: ------------------------------
> Jul 14 14:51:20 qwiff /kernel: 000: 00 00 10 08 00 00 00 00 00 00 04 00 90
^^
But my advise was partially botched. The code still tries to select
density 0 in your drive, but now without doing the block mode decision
inside the driver (so it apparently takes it from the rogue table).
I wonder why this happened.
When comparing with the SCSIDEBUG output from my TDC4222, it looks
like this device requires a valid density and doesn't grok density 0
(which means ``default density'' -- one would assume it should always
accept this).
I wonder whether we should always use the following kludge:
Index: sys/scsi/st.c
===================================================================
RCS file: /home/ncvs/src/sys/scsi/st.c,v
retrieving revision 1.36.4.1
diff -u -u -r1.36.4.1 st.c
--- st.c 1995/07/22 04:25:10 1.36.4.1
+++ st.c 1996/07/14 10:25:07
@@ -1530,7 +1530,9 @@
scsi_cmd.length = dat_len;
dat.header.blk_desc_len = sizeof(struct blk_desc);
dat.header.dev_spec |= SMH_DSP_BUFF_MODE_ON;
- dat.blk_desc.density = st->density;
+ dat.blk_desc.density =
+ st->density? st->density:
+ 0x7f /* use previous density */;
if (st->flags & ST_FIXEDBLOCKS) {
scsi_uto3b(st->blksiz, dat.blk_desc.blklen);
}
It forces the density set to the ``use previous density'' value per
the SCSI specs in case the current value is 0. (If i read the specs
correctly, the latter is a ``Can't happen'' condition since a tape
device is not supposed to ever return density 0. The Tandberg does,
however.)
Could you try both? First, remove the bogus ST_Q_NEEDS_PAGE_0. If
this works, try disabling the quirk record entirely, and see whether
the above patch would also solve the problem. If the latter works for
you, i think it is safe to commit it as a general failsafe option.
Here's the quirk record patch again in a slightly different version:
Index: sys/scsi/st.c
===================================================================
RCS file: /home/ncvs/src/sys/scsi/st.c,v
retrieving revision 1.36.4.1
diff -u -u -r1.36.4.1 st.c
--- st.c 1995/07/22 04:25:10 1.36.4.1
+++ st.c 1996/07/14 10:36:50
@@ -113,6 +113,15 @@
{0, 0, QIC_120} /* minor 12,13,14,15 */
}
},
+ {"Tandberg tdc4100", "TANDBERG", " TDC 4100", "????",
+ ST_Q_NEEDS_PAGE_0|ST_Q_SNS_HLP,
+ {
+ {0, 0, 0}, /* minor 0,1,2,3 */
+ {0, ST_Q_FORCE_VAR_MODE, QIC_525}, /* minor 4,5,6,7 */
+ {0, ST_Q_FORCE_VAR_MODE, 0x15}, /* minor 8,9,10,11 */
+ {512, ST_Q_FORCE_FIXED_MODE, QIC_150} /* minor 12,13,14,15 */
+ }
+ },
{"Rev 5 of the Archive 2525", "ARCHIVE ", "VIPER 2525 25462", "-005",
0,
{
It's now supposed to force subdevice 1 (/dev/rst0.1) into QIC-525
variable length, subdevice 2 into QIC-1GB variable length, and
subdevice 3 into QIC-150 512-byte records. Failing any form of usable
autodetection (subdevice 0), this is supposed to supply safe defaults.
--
cheers, J"org
joerg_wunsch@uriah.heep.sax.de -- http://www.sax.de/~joerg/ -- NIC: JW11-RIPE
Never trust an operating system you don't have sources for. ;-)
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