atapicam hangs system

[Daniel Lang]

Hi hackers,

following a problem I currently discuss with Thomas
(maintainer of atapicam). Since it turned into some
kernel debugging issues, I think I could use input from
-hackers, as well.

Summary: System (SCSI bus?) hangs, after using an ATAPI CD-RW
         device via the atapicam layer.

atapicam is the only ATA device option in the kernel
(so no acd# devices, just cd#).

Original Message follows:

Thomas Quinot wrote on Tue, Jul 08, 2003 at 08:48:38PM +0200:
[..]
> Your problem sounds like the ATA bus hanging. When it hangs and you can
> still access your xterms, it would be nice to see what dmesg says.
> You can also try to trigger the hang outside of X, and see if there are
> messages on the console. Another possible solution is to drop into DDB
> using Ctrl+Alt+Esc, and then manually trigger a panic.
[..]
> BTW, you're using the latest -STABLE kernel, right?
[..]

So, back in the office, I went back to the issue. Before anything
else, I've updated my system to 4.8-STABLE, then built a
debugging kernel with options DDB.

uname -a:
FreeBSD atrbg11.informatik.tu-muenchen.de 4.8-STABLE FreeBSD 4.8-STABLE #19: MonJul 14 18:17:20 CEST 2003     root at atrbg11.informatik.tu-muenchen.de:/usr/obj/usr/src/sys/ATRBG11  i386

I did not start X but worked on the console. I used cdrdao to write
a cdimage:

# camcontrol devlist
<IBM DNES-318350W SA30>            at scbus0 target 1 lun 0 (pass0,da0)
<FUJITSU MAM3367MP 0106>           at scbus0 target 2 lun 0 (pass1,da1)
<TOSHIBA CD-ROM XM-6602B 1017>     at scbus1 target 0 lun 0 (pass2,cd0)
<HL-DT-ST CD-RW GCE-8520B 1.00>    at scbus2 target 0 lun 0 (pass3,cd1)

The last one is the cd writer I've used with the following command:

# cdrdao write --device 2,0,0 --driver generic-mmc --speed 48 -v 2 -n bla.toc

After two successful writes, the system hung again, as before.
Unfortunately there are _no_ messages on the console.

I entered the debugger with Ctrl-Alt-Esc and did a trace.
I did not copy everything, because I thought I could use gdb -k
later on (I was wrong). However, what I've saved from the trace was:

Apparently the system hung in

camisr(c02f3250,c02b7078,c253aa3,0,10) at camisr+0x8f

eip: 0xc01279d7, esp: 0xc0297008, ebp: 0xc0297020

Please advice what to examine how.

Forcing a panic did not work. I could call panic, but
'continue' did not write a crash dump to disk, but hung again.

call boot(0) did not work, too and from this on, I could not even 
get back into the debugger and had to hit the reset button.

So it seems that scsi disk operations are not working as well,
so maybe not the ATA bus is hanging but the SCSI subsystem?

Remote-GDB debugging is not an option, unfortunately. I don't have
another RELENG_4 machine ready. However, I have a laptop with
some half-working 5.1-CURRENT. There are no 4.x sources on it...
maybe it could work, if I copy the source tree, but I would like
to have some confirmation, that it works, before I put effort
into this.

Please advise. :)

Best regards,
 Daniel
-- 
IRCnet: Mr-Spock                      - May His Shadow fall upon thee - 
 Daniel Lang * dl at leo.org * +49 89 289 18532 * http://www.leo.org/~dl/
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