Re: "aborting sbp2 command" expected in kernel.org FireWire maybe

Stefan R:

> > serialize_io ...
> reasonable to include this option in a distro.
> sbp2_serialize_io ... the default for the linux-2.4 branch since
revision 1227.
> may avoid ... faulty SBP-2 bridge firmware ... may also mask bugs in
... Linux ...

More clear than ever now, thank you.

Can I next help discover whether this bug we have found is in the
device or in Linux or both?

> I don't think the new drives use
> any vendor specific commands today, or do they?

I agree. I haven't yet written code to print every op, but at random I
have seen no vendor-specific ops involved, instead I see "aborting sbp2
command" trace only the ordinary ops that I expect for any read and
write of DVD-RAM discs, such as x 00 1B 1E 28 2A ....

> Your system always chokes on [op x28] "Read (10)"
> anyway,

I agree. I remember also sometimes I see "aborting sbp2 command" with
an op x1B "START STOP UNIT" used to mean eject, and maybe with some
other ops.

> [op x28] "Read (10)" ....
> is not at all special to DVD-ROM/R/RW.

I agree. Of course, the conversion between blocks and bytes varies
between HDD and DVD. The HDD convention is 0.5 KiB/LBA, the DVD/ CD
convention is 2 KiB/LBA. I saw block/drivers/ub.c choke over this
lately, but the hard-coded 512 were easy to find and fix in that source
code.

> modprobe.conf ... present, ... I assume ... in a 2.6 based
distribution).

Thanks for asking, actually I see ...

No /etc/modprobe.conf present by default in the 2.6.7 of Knoppix 3.6.
All the same, yes, creating an /etc/modprobe.conf containing the one
line of 2.6 syntax "options sbp2 serialize_io=1" does work i.e. the
next explicit modprobe sbp2 does produce the dmesg: sbp2: Driver forced
to serialize ....

> > I ... see the Knoppix 2.6 boot complain: ...
> > 281 sbp2: Unknown parameter `sbp2_serialize_io'
> > 282 sbp2: $Rev: 1219 $ Ben Collins

This result I do not yet understand, since in Knoppix no
/etc/modprobe.conf exists by default. sudo grep -ilr serialize_io /etc
initially instead finds only:

/etc/modules.conf
/etc/modutils/options

Both of those files have only the 2.4 syntax, and indeed the entire
content of /etc/modutils/options is the one line of 2.4 syntax "options
sbp2 sbp2_serialize_io=1".

I conclude that Knoppix dmesg of "sbp2: Unknown parameter
`sbp2_serialize_io'" during boot is coming from somewhere not
accurately simulated by trying, after boot, the composite command:

modprobe -r sbp2 ; modprobe sbp2

> kernel 2.4 ... default ... options ... /etc/modules.conf
> kernel 2.6 ... /etc/modprobe.conf

New to me, thanks for saying. Personally before now I haven't needed
to persistently override any module parameter defaults. modprobe.conf
and modules.conf are strings that as yet do not appear in the
intermittently available FAQ for kernel folk moving to 2.6 from 2.4:

http://www.codemonkey.org.uk/post-halloween-2.5.txt

Pat LaVarre

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Received on Fri Sep 17 18:45:29 2004