Re: mesh SCSI bus locks hard on 7500 when burning a CD-R in dao mode

On Tue, Jan 30, 2001 at 10:46:06PM +0100, Michael Schmitz [off-list ref] wrote:

quoted

quoted

The big question: why does this particular command time out in the first
place? Does the target expect more data to be sent? Does the target just
crash and fails to release the bus? It seems to work on other host
adapters, doesn't it?

There's a report of excatly the same failure mode on mac53c94 with a
different brand (Sony, as opposed to Yamaha on my MESH) of DVD drive.

Please send a detailed description on how to reproduce this bug by PM.
I'll try to look into that on my Lombard, and in case I can get the
required binaries for m68k I'd also test on an old Quadra with 53c9x
SCSI.

Basically, any time I have used cdrdao to write a disc, or cdrecord with
the -dao flag, the SCSI bus has locked up, under kernels from 2.2.15pre3
or so to a recent 2.4 from the bk tree.  I'm tempted to see whether I
can write a short program using the sg stuff to just send the
"send_cue_sheet" command to the CD-RW and see if it locks up, but I
haven't had a chance to look into it yet.

Does the bug happen only with DVD writers, or regular CD writers?

Aargh, sorry, when I said "DVD" above it was a complete thinko.  I have
a Yamaha CD-RW drive (the model number is something wit 8424 in it, I
can get exact details when I get home.)  The report with the mac53c94
driver was a Sony CD-R or CD-RW drive -- I've exchanged email with the
guy who reported it and can ask for the details if you'd like.  I have
no idea if it would fail with a DVD writer, but all the cases I've seen
have been CD writers.  (This is why it's not a good idea to wait until
late afternoon to have coffee, and why if I do so, I should refrain from
writing email until after I have found some.)  :-)

quoted

So the only points in common seem to be that the DVD drives are running
on mac hardware and that the drivers are written by Paul Mackerras.  :-)
I don't at all mean to impugn Paul's coding ability, which is obviously
excellent, but the fact that he wrote both the drivers may mean that
they share lots of code and possibly share the same bug.

If so, the bug should have propagated to the m68k 53c9x driver. Wouldn't
be the 53c9x first weirdness - I never got it to accept a DAT drive (old
DDS-1, possibly Apple) without blowing up.

It would be great if you could check this out.

It might be something PPC specific as well and have nothing to do with
Paul's drivers.

This is why I asked in a previous email whether anyone had ever burned
a disk in DAO mode successfully on a pmac or in fact on any powerpc
machine, but I've received no responses.  Hmm, maybe I should try to
conduct a quick survey of this on linuxppc-user and/or debian-powerpc.

-Daniel

--
Daniel E. Eisenbud
eisenbud@cs.swarthmore.edu

** Sent via the linuxppc-dev mail list. See http://lists.linuxppc.org/

quoted

It might be something PPC specific as well and have nothing to do with
Paul's drivers.

This is why I asked in a previous email whether anyone had ever burned
a disk in DAO mode successfully on a pmac or in fact on any powerpc
machine, but I've received no responses.  Hmm, maybe I should try to
conduct a quick survey of this on linuxppc-user and/or debian-powerpc.

Well, I can't write a dao disk on my Panasonic CW-7502.  cdrecord complains
that it can't send the cue sheet, but the SCSI bus doesn't die in any way, I
can still mount and use disks on it afterwards (I only have the built-in
CD-ROM and my CD-R on it).  I can provide exactly what cdrecord says and any
other info if you wish.

This is on a Performa 5400/180 with an early pull of the 2.4.0 kernel from
bk.  Everything seems to be working fine, except for this (which isn't too
important for me).

Good luck,

--
    .-.        Chris Boot
    /v\     bootc@worldnet.fr
   // \\
  /(   )\   L   I   N   U   X
   ^^-^^   >Phear the Penguin<


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